Process of rheology modification of polymers

ABSTRACT

The invention includes a process of reacting a poly(sulfonyl azide) with a polymer comprising steps (a) forming a first admixture, hereinafter referred to as a concentrate, of a first amount of a first polymer or in a liquid which does not require removal from the polymer, hereinafter diluent, and a poly(sulfonyl azide); (b) then forming a second admixture of the first admixture with a second amount of at least one second polymer, hereinafter second polymer composition; and (c) heating the second admixture at least to the decomposition temperature of the coupling agent for a time sufficient to result in coupling of polymer chains. The diluent is preferably a non-volatile, non-polar compound such as mineral oil in which the poly(sulfonyl azide) is sufficiently miscible to disperse the poly(sulfonyl azide) in the second polymer, more preferably a liquid at room temperature or low melting solid at room temperature, that is has a melting point below about 50° C. When a first polymer is used, it is preferably low melting, and most preferably is selected from ethylene alpha olefin copolymers; ethylene acrylic acid; ethylene vinyl acetate, ethylene/styrene interpolymers or combinations thereof. The concentrate is optionally formed on the surface of a polymer to be coupled. Step (b) preferably takes place in melt processing equipment; more preferably steps (a) and (b) take place in the same vessel, which is preferably in the post-reactor area of a polymer processing plant. The invention further includes all compositions obtainable by processes of the invention as well as blends of those compositions with one or more polymers of compositions different from the first or second polymer or the product of a process of the invention. Additionally the invention includes articles made from compositions of the invention, and shaping those articles particularly by processes which comprise shaping the compositions in a melted state into an article, more preferably when the process comprises thermoforming, injection molding, extrusion, casting, blow molding, foaming or blowing as well as the use of the compositions in those processes.

[0001] This application claims the benefit of U.S. ProvisionalApplication No. 60/057582, filed Aug. 27, 1997 which is herebyincorporated by reference herein in its entirety.

[0002] This invention relates to coupling of polyolefins, morespecifically coupling of polyolefins using insertion into carbonhydrogen (C—H) bonds.

[0003] As used herein, the term “rheology modification” means change inmelt viscosity of a polymer as determined by dynamic mechanicalspectroscopy. Preferably the melt strength increases while maintainingthe high shear viscosity (that is viscosity measured at a shear of 100rad/sec by DMS) so that a polymer exhibits more resistance to stretchingduring elongation of molten polymer at low shear conditions (that isviscosity measured at a shear of 0.1 rad/sec by DMS) and does notsacrifice the output at high shear conditions. An increase in meltstrength is typically observed when long chain branches or similarstructures are introduced into a polymer.

[0004] Polyolefins are frequently rheology modified using nonselectivechemistries involving free radicals generated for instance usingperoxides or high energy radiation. However, chemistries involving freeradical generation at elevated temperatures also degrade the molecularweight, especially in polymers containing tertiary hydrogen such aspolystyrene, polypropylene, polyethylene copolymers etc. The reaction ofpolypropylene with peroxides and pentaerythritol triacrylate is reportedby Wang et al., in Journal of Applied Polymer Science, Vol. 61,1395-1404 (1996). They teach that rheology modification of isotacticpolypropylene can be realized by free radical grafting of di- andtri-vinyl compounds onto polypropylene. However, this approach does notwork well in actual practice as the higher rate of chain scission tendsto dominate the limited amount of chain coupling that takes place. Thisoccurs because chain scission is an intra-molecular process followingfirst order kinetics, while coupling is an inter-molecular process withkinetics that are minimally second order. Chain scission results inlower molecular weight and higher melt flow rate than would be observedwere the branching not accompanied by scission. Because scission is notuniform, molecular weight distribution increases as lower molecularweight polymer chains referred to in the art as “tails” are formed.

[0005] The teachings of U.S. Pat. Nos. 3,058,944; 3,336,268; and3,530,108 include the reaction of certain poly(sulfonyl azide) compoundswith isotactic polypropylene or other polyolefins by nitrene insertioninto C—H bonds. The product reported in U.S. Pat. No. 3,058,944 iscrosslinked. The product reported in U.S. Pat. No. 3,530,108 is foamedand cured with cycloalkane-di(sulfonyl azide) of a given formula. InU.S. Pat. No. 3,336,268 the resulting reaction products are referred toas“bridged polymers” because polymer chains are “bridged” withsulfonamide bridges. The disclosed process includes a mixing step suchas milling or mixing of the sulfonylazide and polymer in solution ordispersion then a heating step where the temperature is sufficient todecompose the sulfonylazide (100° C. to 225° depending on the azidedecomposition temperature). The starting polypropylene polymer for theclaimed process has a molecular weight of at least about 275,000. Blendstaught in U.S. Pat. No. 3,336,268 have up to about 25 percent ethylenepropylene elastomer.

[0006] U.S. Pat. No. 3,631,182 taught the use of azido formate forcrosslinking polyolefins. U.S. Pat. No. 3,341,418 taught the use ofsulfonyl azide and azidoformate compounds to crosslink of thermoplasticsmaterial(PP (polypropylene), PS (polystyrene), PVC (poly(vinylchloride)) and their blends with rubbers (polyisobutene, EPM, etc.).

[0007] Similarly, the teachings of Canadian patent 797,917 (familymember of NL 6,503,188) include rheology modification using from about0.001 to 0.075 weight percent polysulfonyl azide to modify homopolymerpolyethylene and its blend with polyisobutylene.

[0008] Teachings of incorporating poly(sulfonyl azides) into polymers inthese references are typically directed to mixing poly(sulfonyl azide)as a solid or in a solvent into a polymer. Disadvantageously, mixingsolids often results in localized concentrations of azide which evidencethemselves as gels, discoloration, for instance black specks, or unevenamounts of coupling. Using a solvent, however, requires an extra step ofremoving solvent and sometimes equipment adaptations for the removal andhandling volatile chemicals.

[0009] It would be desirable to avoid dark specks, gels and otherevidence of localized poly(sulfonyl azide) and to avoid removing orhandling solvent yet to obtain polymers rheology modified rather thancrosslinked (that is having less than about 10 percent gel as determinedby xylene extraction specifically by ASTM 2765). Which polymers, in thecase of high density polyethylene are desirably of narrow molecularweight distribution (MWD) (that is having most preferably less thanabout 3.0 Mw/Mn, and preferably density greater than 0.945 g/ml)advantageously made using single site, single site metallocene or singlesite constrained geometry catalysts (hereinafter HDPE of narrow MWD)which polymers advantageously have a combination of good processabilityas indicated by higher melt strength at a constant low shear viscositye.g. 0.1 rad/sec measured by DMS, and higher toughness, tensile and/orelongation than a high density polyethylene of broader molecular weightdistribution treated with sulfonyl azides according to the practice ofthe prior art using the same equivalents (stoichiometry) of couplingreactant to polymer higher toughness than that of the same startingmaterial coupled or rheology modified using the same equivalents of afree radical coupling agent Desirably, the product would have betterorganoleptics than coupled broader MWD HDPE. Advantageously,compositions would have less undesirable odor than the same startingmaterials coupled or rheology modified using the same chemicalequivalents of free radical generating agents. Preferably, a process ofthe invention would result in more consistent coupling than methods ofcoupling involving free radicals, that is use of the same reactants,amounts and conditions would result in consistent amounts of coupling orconsistent (reproducible) property changes, especially consistentamounts of gel formation. Preferably, a process would be less subject toeffects from the presence of oxygen than would a coupling or rheologymodification involving agents which generate free radicals.

[0010] In the case of, medium and lower density polyethylene (that ispolymers having a density of from about 0.94 g/cc to about 0.90 g/cc),which are advantageously copolymers of ethylene in which the percentcomonomer is preferably about 0.5 to 5 mole percent comonomer based ontotal polymer as determined by ASTM 5017, the polymers would desirablyshow a combination of processability improved over the starting materialwith retention of toughness, low heat seal initiation temperature, lowhaze, high gloss or hot tack properties characteristic of the startingmaterial.

[0011] In the case of elastomeric polymers containing ethylene repeatingunits in which the preferred comonomer content is about 5-25 molepercent, and preferably a density less than about 0.89 g/mL, it would bedesirable to have a better mechanical properties such as elongation andtensile strength than would be achieved in the starting material or bycoupling using the same chemical equivalents of free radical generatingagent like a peroxide.

SUMMARY OF THE INVENTION

[0012] Polymers coupled by reaction with coupling agents according tothe practice of the invention advantageously have at least one of thesedesirable properties and preferably have desirable combinations of theseproperties.

[0013] The invention includes a process of reacting a poly(sulfonylazide) with a polymer comprising steps (a) forming a first admixture,hereinafter referred to as a concentrate, of a first amount of a firstpolymer or in a liquid which does not require removal from the polymer,hereinafter diluent, and a poly(sulfonyl azide); (b) then forming asecond admixture of the first admixture with a second amount of at leastone second polymer, hereinafter second polymer composition; and (c)heating the second admixture at least to the decomposition temperatureof the coupling agent for a time sufficient to result in coupling ofpolymer chains. The diluent is preferably a non-volatile, non-polarcompound such as mineral oil in which the poly(sulfonyl azide) issufficiently miscible to disperse the poly(sulfonyl azide) in the secondpolymer, more preferably a liquid at room temperature or low meltingsolid at room temperature, that is has a melting point below about 50°C. When a first polymer is used, it is preferably low melting, that ishas a melting point below about 150° C., more preferably 110° C., or amelt index, I2, of at least about 0.5 g/10 min. and most preferably isselected from ethylene alpha olefin copolymers, where the alpha olefinsare of 3 to 20 carbon atoms, have a density range of at least about0.855 g/cc to about 0.955 g/cc or have a melt index, I2, of at leastabout 0.5 g/10 min; ethylene acrylic acid; ethylene vinyl acetate,ethylene/styrene interpolymers or combinations thereof. The concentrateis optionally formed on the surface of a polymer to be coupled. Step (b)preferably takes place in melt processing equipment; more preferablysteps (a) and (b) take place in the same vessel, which is preferably inthe post-reactor area of a polymer processing plant.

[0014] The invention further includes all compositions obtainable byprocesses of the invention as well as blends of those compositions withone or more polymers of compositions different from the first or secondpolymer or the product of a process of the invention. Additionally theinvention includes articles made from compositions of the invention, andshaping those articles particularly by processes which comprise shapingthe compositions in a melted state into an article, more preferably whenthe process comprises thermoforming, injection molding, extrusion,casting, blow molding, foaming or blowing as well as the use of thecompositions in those processes.

DETAILED DESCRIPTION OF THE INVENTION

[0015] Practice of the invention is applicable to any thermoplasticpolymer which has at least one C—H bond that can react with azideincluding homopolymers and copolymers with narrow and broad (includingbimodal) comonomer distribution (narrow and broad, including bimodal,molecular weight distribution) such as copolymers of ethylene with oneor more alpha olefin (C3 to C20), ethylene copolymers with unsaturation(EPDM or EODM, that is ethylene-propylene-diene or ethylene-octene-diene), or other polymers such as linear high density polyethylene,LDPE (low density polyethylene), ethylene vinyl acetate copolymers,ethylene acrylic acid copolymers, styrene based block copolymers (SBS,SEBS, SIS and the like, that is styrene/butadiene/styrene,styrene/ethylene/butylene/styrene (hydrogenated SEBS),styrene/isoprene/styrene and the like), substantially randominterpolymers of at least one alpha-olefin with at least one vinylaromatic or hindered vinyl aliphatic comonomer includingethylene-styrene interpolymers, syndiotatic polystyrene, atacticpolystyrene, hydrogenated polyvinyl cyclohexene, PET (poly(ethyleneterephthalate)), PBT (polybutylene terephthalate), PEN (polyethylenenaphthalate), polylactic acid, thermoplastic polyurethanes,polycarbonate, nylon, poly(methyl methacrylates), ABS(acrylonitrile/butylene/styrene), polysulfone, polyphenylene oxide,polyphenylene sulfides, polyacetal and polyvinyl chloride.

[0016] Preferred polymers for use in the practice of the invention arepolymers prepared from ethylene, advantageously ethylene in combinationwith other monomers polymerizable therewith. Such monomers include alphaolefins and other monomers having at least one double bond.

[0017] Alpha olefins having more than 2 carbon atoms include propylene,1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene,1-unidecene, 1-dodecene and the like as well as 4-methyl-1-pentene,4-methyl -1-hexene, 5-methyl-1-hexene, vinylcyclohexene, styrene and thelike.

[0018] Interpolymers useful in the practice of the invention optionallyand in one preferred embodiment include monomers having at least twodouble bonds which are preferably dienes or trienes. Suitable diene andtriene comonomers include 7-methyl-1,6-octadiene, 3,7-dimethyl-1,6-octadiene, 5,7-dimethyl-1,6-octadiene,3,7,11-trimethyl-1,6,10-octatriene, 6-methyl-1,5-heptadiene,1,3-butadiene, 1,6-heptadiene, 1,7-octadiene, 1,8-nonadiene,1,9-decadiene, 1,10-undecadiene, bicyclo[2.2.1]hepta-2-5-diene(norbornadiene), tetracyclododecene, or mixtures thereof, preferablybutadiene, hexadienes, and octadienes, most preferably 1,4-hexadiene,4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, dicyclopentadiene,bicyclo[2.2.1]hepta-2-5-diene (norbornadiene) and5-ethylidene-2-norbornene.

[0019] Polymers useful in the practice of the invention also optionallyinclude repeating units formed from monomers having functional groupssuch as carboxylic acid and esters, alcohol, or amine groups, halogen(advantageously chlorine, bromine, or fluorine, preferably chlorine orfluorine). Such monomers include acrylic acid, methacrylic acid, vinylchloride, vinylidene chloride, vinyl acetate, alkyl esters, particularlyethyl, methyl, or butyl acrylate or methacrylate or carbon monoxide

[0020] Polyolefins are formed by means within the skill in the art. Thealpha olefin monomers and optionally other addition polymerizablemonomers are polymerized under conditions within the skill in the art,Such conditions include those utilized in processes involvingZiegler-Natta catalysts such as those disclosed in U.S. Pat. No.4,076,698 (Anderson et al); U.S. Pat. No. 4,950,541 and the patents towhich they refer, as well as U.S. Pat. No. 3,645,992 (Elston) as well asthose processes utilizing metallocene and other single site catalystssuch as exemplified by U.S. Pat. No. 4,937,299 (Ewen et al.), U.S. Pat.No. 5,218,071 (Tsutsui et al.), U.S. Pat. Nos. 5,278,272, 5,324,800,5,084,534, 5,405,922, 4,588,794, 5,204,419 and the processessubsequently discussed in more detail.

[0021] In one embodiment, starting material polyolefins are preferablysubstantially linear ethylene polymers (SLEPs). The substantially linearethylene polymers (SLEPs) are homogeneous polymers having long chainbranching. They are disclosed in U.S. Pat. Nos. 5,272,236 and 5,278,272,the disclosures of which are incorporated herein by reference. SLEPs areavailable as polymers made by the Insite™ Process and CatalystTechnology such as Engage™ polyolefin elastomers (POEs) commerciallyavailable from DuPont Dow Elastomers LLC and Affinity™ polyolefinplastomers (POPs) commercially available from The Dow Chemical Company.Specific examples of useful Engage™ POEs include SM 8400, EG 8100, andCL 8001 and specific examples of useful Affinity™ POPs include FM-1570,HM 1100, and SM 1300, each of which is commercially available from TheDow Chemical Company. SLEPs can be prepared via the solution, slurry, orgas phase, preferably solution phase, polymerization of ethylene and oneor more optional α-olefin comonomers in the presence of a constrainedgeometry catalyst, such as is disclosed in European Patent Application416,815-A, incorporated herein by reference.

[0022] The substantially linear ethylene/α-olefin polymers are made by acontinuous process using suitable constrained geometry catalysts,preferably constrained geometry catalysts as disclosed in U.S.application Ser. No. 545,403, filed Jul. 3, 1990; Ser. No. 758,654,filed Sep. 12, 1991; Ser. No. 758,660, filed Sep. 12, 1991; and Ser. No.720,041, filed Jun. 24, 1991, the teachings of all of which areincorporated herein by reference. The monocyclopentadienyl transitionmetal olefin polymerization catalysts taught in U.S. Pat. No. 5,026,798,the teachings of which is incorporated herein by reference, are alsosuitable for use in preparing the polymers of the present invention, solong as the reaction conditions are as specified below.

[0023] Suitable cocatalysts for use herein include but are not limitedto, for example, polymeric or oligomeric aluminoxanes, especially methylaluminoxane, as well as inert, compatible, noncoordinating, ion formingcompounds. Preferred cocatalysts are inert, noncoordinating, boroncompounds.

[0024] The expression “continuous process” means a process in whichreactants are continuously added and product is continuously withdrawnsuch that an approximation of a steady state (i.e. substantiallyconstant concentration of reactants and product while carrying out theprocess) is achieved. The polymerization conditions for manufacturingthe substantially linear ethylene/α-olefin polymers of the presentinvention are generally those useful in the solution polymerizationprocess, although the application of the present invention is notlimited thereto. Slurry and gas phase polymerization processes are alsobelieved to be useful, provided the proper catalysts and polymerizationconditions are employed.

[0025] Multiple reactor polymerization processes can also be used inmaking the substantially linear olefin polymers and copolymers to berheologically modified according to the present invention, such as thosedisclosed in U.S. Pat. No. 3,914,342, incorporated herein by reference.The multiple reactors can be operated in series or in parallel, with atleast one constrained geometry catalyst employed in one of the reactors.

[0026] The term “substantially linear” means that in addition to theshort chain branches attributable to homogeneous comonomerincorporation, the ethylene polymer is further characterized as havinglong chain branches in that the polymer backbone is substituted with anaverage of 0.01 to 3 long chain branches/1000 carbons. Preferredsubstantially linear polymers for use in the invention are substitutedwith from 0.01 long chain branch/1000 carbons to I long chainbranch/1000 carbons, and more preferably from 0.05 long chainbranch/1000 carbons to 1 long chain branch/1000 carbons.

[0027] In contrast to the term “substantially linear”, the term “linear”means that the polymer lacks measurable or demonstrable long chainbranches, i.e., the polymer is substituted with an average of less than0.01 long chain branch/1000 carbons.

[0028] For ethylene/(α-olefin interpolymers, “long chain branching”(LCB) means a chain length longer than the short chain branch thatresults from the incorporation of the α-olefin(s) into the polymerbackbone. Each long chain branch has the same comonomer distribution asthe polymer backbone and can be as long as the polymer backbone to whichit is attached.

[0029] The empirical effect of the presence of long chain branching inthe substantial linear ethylene/α-olefin interpolymers used in theinvention is manifested in its enhanced rheological properties which arequantified and expressed herein in terms of gas extrusion rheometry(GER) results and/or melt flow, I₁₀/I₂, increases.

[0030] The presence of short chain branching of up to 6 carbon atoms inlength can be determined in ethylene polymers by using ¹³C nuclearmagnetic resonance (NMR) spectroscopy and is quantified using the methoddescribed by Randall (Rev. Macromol. Chem. Phys., C.29, V. 2&3, p285-297), the disclosure of which is incorporated herein by reference.

[0031] As a practical matter, current ¹³C nuclear magnetic resonancespectroscopy cannot distinguish the length of a long chain branch inexcess of six carbon atoms. However, there are other known techniquesuseful for determining the presence of long chain branches in ethylenepolymers, including ethylene/1-octene interpolymers. Two such methodsare gel permeation chromatography coupled with a low angle laser lightscattering detector (GPC-LALLS) and gel permeation chromatographycoupled with a differential viscometer detector (GPC-DV). The use ofthese techniques for long chain branch detection and the underlyingtheories have been well documented in the literature. See, e.g., Zimm,G. H. and Stockmayer, W. H., J.Chem. Phys., 17,1301 (1949) and Rudin, A.Modern Methods of Polymer Characterization, John Wiley & Sons, New York(1991) pps 103-112, both of which are incorporated by reference.

[0032] A Willem deGroot and P. Steve Chum, both of The Dow ChemicalCompany, at the Oct. 4, 1994 conference of the Federation of AnalyticalChemistry and Spectroscopy Society (FACSS) in St. Louis, Mo., presenteddata demonstrating that GPC-DV is a useful technique for quantifying thepresence of long chain branches in SLEPs. In particular, deGroot andChum found that the level of long chain branches in homogeneoussubstantially linear homopolymer samples measured using theZimm-Stockmayer equation correlated well with the level of long chainbranches measured using ¹³C NMR

[0033] Further, deGroot and Chum found that the presence of octene doesnot change the hydrodynamic volume of the polyethylene samples insolution and, as such, one can account for the molecular weight increaseattributable to octene short chain branches by knowing the mole percentoctene in the sample. By deconvoluting the contribution to molecularweight increase attributable to 1-octene short chain branches, deGrootand Chum showed that GPC-DV may be used to quantify the level of longchain branches in substantially linear ethylene/octene copolymers

[0034] deGroot and Chum also showed that a plot of Log (I₂) as afunction of Log (M_(w)) as determined by GPC illustrates that the longchain branching aspects (but not the extent of long branching) of SLEPsare comparable to that of high pressure, highly branched low densitypolyethylene (LDPE) and are clearly distinct from ethylene a polymersproduced using Ziegler-type catalysts such as titanium complexes andordinary catalysts for making homogeneous polymers such as hafnium andvanadium complexes.

[0035] SLEPs are further characterized as having:

[0036] (a) a melt flow ratio, I₁₀/I₂≧5.63,

[0037] (b) a molecular weight distribution, M_(w)/M_(n) as determined bygel permeation chromatography and defined by the equation:

(M _(w) /M _(n))≦(I ₁₀ /I ₂)−4.63,

[0038] (c) a critical shear stress at the onset of gross melt fracture,as determined by gas extrusion rheometry, of greater than 4×10⁶dynes/cm² or a gas extrusion rheology such that the critical shear rateat onset of surface melt fracture for the SLEP is at least 50 percentgreater than the critical shear rate at the onset of surface meltfracture for a linear ethylene polymer, the linear ethylene polymer hasan I₂, M_(w)/M_(n) and, preferably density, which are each within tenpercent of the SLEP and wherein the respective critical shear rates ofthe SLEP and the linear ethylene polymer are measured at the same melttemperature using a gas extrusion rheometer, and, preferably,

[0039] (d) a single differential scanning calorimetry, DSC, melting peakbetween −30 and 150° C.

[0040] For the substantially linear ethylene/α-olefin polymers used inthe compositions of the invention, the I₁₀/I₂ ratio indicates the degreeof long chain branching, i.e., the higher the I₁₀/I₂ ratio, the morelong chain branching in the polymer. Generally, the I₁₀/I₂ ratio of thesubstantially linear ethylene/α-olefin polymers is at least about 5.63,preferably at least about 7, especially at least about 8 or above, andas high as about 25.

[0041] The melt index for the substantially linear olefin polymersuseful herein is preferably at least about 0.1 grams/10 minutes (g/10min), more preferably at least about 0.5 g/10 min and especially atleast about 1 g/10 min up to preferably about 100 g/10 min, morepreferably up to about 50 g/10 min, and especially up to about 20 g/10min.

[0042] Determination of the critical shear rate and critical shearstress in regards to melt fracture as well as other rheology propertiessuch as rheological processing index (PI), is performed using a gasextrusion rheometer (GER). The gas extrusion rheometer is described byM. Shida, R. N. Shroff and L. V. Cancio in Polymer Engineering Science,Vol. 17, No. 11, p. 770 (1977), and in Rheometers for Molten Plastics byJohn Dealy, published by Van Nostrand Reinhold Co. (1982) on pp. 97-99,both of which are incorporated by reference herein in their entirety.GER experiments are generally performed at a temperature of 190° C., atnitrogen herein, the PI is the apparent viscosity (in kpoise) of amaterial measured by GER at an apparent shear stress of 2.15×10⁶dyne/cm². The SLEPs for use in the invention includes ethyleneinterpolymers and have a PI in the range of 0.01 kpoise to 50 kpoise,preferably 15 kpoise or less. The SLEPs used herein have a PI less thanor equal to 70 percent of the PI of a linear ethylene polymer (either aZiegler polymerized polymer or a linear uniformly branched polymer asdescribed by Elston in U.S. Pat. No. 3,645,992) having an I₂,M_(w)/M_(n) and density, each within ten percent of the SLEPs.

[0043] The Theological behavior of SLEPs can also be characterized bythe Dow Rheology Index (DRI), which expresses a polymer's “normalizedrelaxation time as the result of long chain branching.” (See, S. Lai andG. W. Knight ANTEC '193 Proceedings, INSITE™ Technology Polyolefins(SLEP)—New Rules in the Structure/Rheology Relationship of Ethyleneα-Oefin Copolymers, New Orleans, La., May 1993, the disclosure of whichis incorporated herein by reference). DRI values range from 0 forpolymers which do not have any measurable long chain branching (e.g.,Tafmer™ products available from Mitsui Petrochemical Industries andExact™ products available from Exxon Chemical Company) to about 15 andare independent of melt index. In general, for low to medium pressureethylene polymers (particularly at lower densities) DRI providesimproved correlations to melt elasticity and high shear flowabilityrelative to correlations of the same attempted with melt flow ratios.For the SLEPs useful in this invention, DRI is preferably at least 0.1,and especially at least 0.5, and most especially at least 0.8. DRI canbe calculated from the equation:

DRI=(3652879*τ_(o) ^(1.00649)/η_(o)−1)/10

[0044] where τ_(o) is the characteristic relaxation time of the materialand nη_(o) is the zero shear viscosity of the material. Both τ_(o) andη_(o) are the “best fit” values to the Cross equation, i.e.,

η/η_(o)=1/(1+(γ* τ_(o))^(1−n))

[0045] in which n is the power law index of the material, and η and γare the measured viscosity and shear rate, respectively. Baselinedetermination of viscosity and shear rate data are obtained using aRheometric Mechanical Spectrometer (RMS-800) under dynamic sweep modefrom 0.1 to 100 radians/second at 190° C. and a Gas Extrusion Rheometer(GER) at extrusion pressures from 1,000 psi to 5,000 psi (6.89 to 34.5MPa), which corresponds to shear stress from 0 086 to 0.43 MPa, using a0.0754 mm diameter, 20:1 L/D die at 190° C. Specific materialdeterminations can be performed from 140 to 190° C. as required toaccommodate melt index variations.

[0046] An apparent shear stress versus apparent shear rate plot is usedto identify the melt fracture phenomena and quantify the critical shearrate and critical shear stress of ethylene polymers. According toRamamurthy in the Journal of Rheology, 30(2), 337-357, 1986, thedisclosure of which is incorporated herein by reference, above a certaincritical flow rate, the observed extrudate irregularities may be broadlyclassified into two main types: surface melt fracture and gross meltfracture.

[0047] Surface melt fracture occurs under apparently steady flowconditions and ranges in detail from loss of specular film gloss to themore severe form of “sharkskin.” Herein, as determined using theabove-described GER, the onset of surface melt fracture (OSMF) isdefined as the loss of extrudate gloss. The loss of extrudate gloss isthe point at which the surface roughness of the extrudate can only bedetected by a 40× magnification. The critical shear rate at the onset ofsurface melt fracture for the SLEPs is at least 50 percent greater thanthe critical shear rate at the onset of surface melt fracture of alinear ethylene polymer having essentially the same 12 and M_(w)/M_(n).

[0048] Gross melt fracture occurs at unsteady extrusion flow conditionsand ranges in detail from regular (alternating rough and smooth,helical, etc.) to random distortions. For commercial acceptability tomaximize the performance properties of films, coatings and moldings,surface defects should be minimal, if not absent. The critical shearstress at the onset of gross melt fracture for the SLEPs, especiallythose having a density >0.910 g/cc, used in the invention is greaterthan 4×10⁶ dynes/cm². The critical shear rate at the onset of surfacemelt fracture (OSMF) and the onset of gross melt fracture (OGMF) will beused herein based on the changes of surface roughness and configurationsof the extrudates extruded by a GER.

[0049] The SLEPs used in the invention are also characterized by asingle DSC melting peak. The single melting peak is determined using adifferential scanning calorimeter standardized with indium and deionizedwater. The method involves 3-7 mg sample sizes, a “first heat” to about180° C. which is held for 4 minutes, a cool down at 10° C./min. to −30°C. which is held for 3 minutes, and heat up at 10° C./min. to 140° C.for the “second heat”. The single melting peak is taken from the “secondheat” heat flow vs. temperature curve. Total heat of fusion of thepolymer is calculated from the area under the curve.

[0050] For polymers having a density of 0.875 g/cc to 0.910 g/cc, thesingle melting peak may show, depending on equipment sensitivity, a“shoulder or a “hump” on the low melting side that constitutes less than12 percent, typically, less than 9 percent, and more typically less than6 percent of the total heat of fusion of the polymer. Such an artifactis observable for other homogeneously branched polymers such as Exact™resins and is discerned on the basis of the slope of the single meltingpeak varying monotonically through the melting region of the artifact.Such an artifact occurs within 34° C., typically within 27° C., and moretypically within 20° C. of the melting point of the single melting peak.The heat of fusion attributable to an artifact can be separatelydetermined by specific integration of its associated area under the heatflow vs. temperature curve.

[0051] The molecular weight distributions of ethylene α-olefin polymersare determined by gel permeation chromatography (GPC) on a Waters 150°C. high temperature chromatographic unit equipped with a differentialrefractometer and three columns of mixed porosity. The columns aresupplied by Polymer Laboratories and are commonly packed with pore sizesof 10³, 10⁴, 10⁵ and 10⁶ Å (10⁻⁴, 10⁻³, 10⁻² and 10⁻¹ mm). The solventis 1,2,4-trichlorobenzene, from which about 0.3 percent by weightsolutions of the samples are prepared for injection. The flow rate isabout 1.0 milliliters/minute, unit operating temperature is about 140°C. and the injection size is about 100 microliters.

[0052] The molecular weight determination with respect to the polymerbackbone is deduced by using narrow molecular weight distributionpolystyrene standards (from Polymer Laboratories) in conjunction withtheir elution volumes. The equivalent polyethylene molecular weights aredetermined by using appropriate Mark-Houwink coefficients forpolyethylene and polystyrene (as described by Williams and Ward inJournal of Polymer Science, Polymer Letters, Vol. 6, p. 621, 1968) toderive the following equation:

M _(polyethylene) =a* (M _(polystyrene))^(b).

[0053] In this equation, a=0.4316 and b=1.0. Weight average molecularweight, M_(W), is calculated in the usual manner according to thefollowing formula: M_(j)=({dot over (Σ)}w_(i)(M_(i) ^(j)))^(j); wherew_(i) is the weight fraction of the molecules with molecular weightM_(i) eluting from the GPC column in fraction i and j=1 when calculatingM_(w) and j=−1 when calculating M_(n).

[0054] The density of the linear or the substantially linear ethylenepolymers (as measured in accordance with ASTM D-792) for use in thepresent invention is generally less than about 0.95 g/cm³. The densityis preferably at least about 0.85 g/cm³ and especially at least about0.86 g/cm³ and preferably up to about 0.94 g/cm³, more preferably up toabout 0.92 g/cm³. When the modified resins are to be used for extrusionand injection molding, the density of the polymer is preferably at least0.855 g/cm³, more preferably at least 0.865 g/cm³, and even morepreferably at least 0.870 g/cm³, up to preferably 0.900 g/cm³, morepreferably 0.885 g/cm³, and even more preferably up to 0.880 g/cm³. Themost preferred density is determined primarily by the modulus ofelasticity or flexibility desired in the molded article. The densityremains substantially constant during rheology modification according tothis invention.

[0055] The ethylene polymers which may be rheology modified according tothis invention may be any interpolymers of ethylene and at least oneα-olefin. Suitable α-olefins are represented by the following formula:

CH₂═CHR

[0056] in which R is a hydrocarbyl radical. R generally has from one totwenty carbon atoms Suitable α-olefins for use as comonomers in asolution, gas phase or slurry polymerization process or combinationsthereof include 1-propylene, 1-butene, 1-isobutylene, 1-pentene,1-hexene, 4-methyl-1-pentene, 1-heptene and 1-octene, as well as othermonomer types such as tetrafluoroethylene, vinyl benzocyclobutane, andcycloalkenes, e.g. cyclopentene, cyclohexene, cyclooctene, andnorbornene (NB). Preferably, the α-olefin will be 1-butene, 1-pentene,4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, or NB, or mixturesthereof. More preferably, the α-olefin will be 1-hexene, 1-heptene,1-octene, or mixtures thereof. Most preferably, the α-olefin will be1-octene. The ethylene polymer rheology modified according to thisInvention is preferably a SLEP.

[0057] These interpolymers preferably contain at least about 2 weightpercent, more preferably at least about 5 weight percent, α-olefin.

[0058] The polyolefin is a homopolymer, copolymer, or interpolymer.Preferably the homo or copolymers contain ethylene repeating units. Inpolyethylene copolymers, the comonomer content is greater than about 1weight percent as determined by ¹³C NMR (carbon 13 nuclear magneticresonance) and more preferably greater than about 3 weight percent ofany monomer copolymerizable with ethylene, preferably an alpha olefin orcyclic olefin, more preferably such an olefin of less than about 20carbon atoms, most preferably from about 2 to about 18 carbon atoms. Thecomonomer content is at least one comonomer polymerizable with ethylene,preferably less than about 4 comonomers polymerizable with ethylene,more preferably less than 2 such comonomers.

[0059] Optionally, however, the practice of this invention includesother hydrocarbon polymers such as polystyrene,poly(stryene-co-acrylonitrile), polyvinylcyclohexene, polybutadiene,polyisoprene, cyclic olefin copolymers and copolymers, and the like, andmixtures thereof. Polymers having at least about 3 weight percentstyrene or substituted styrene units are referred to herein as styrenicpolymers.

[0060] In one embodiment, preferred polymers for starting materialsuseful in the practice of this invention are slurry high densitypolyethylene homopolymers preferably made using single site catalysiswith a narrow MWD (preferably less than about 3.0 Mw/Mn, more preferablyMWD less than about 2.5, most preferably with a density greater thanabout 0.945 g/ml). Preferred melt index of the starting material dependson the desired application; however, the preferred melt index forinjection molding is from about 0.5 to about 50 g/10 min; for film andthermoforming applications the preferred melt index is from about 0.1 toabout 20 g/10 min; and for blow molding applications, the preferred meltindex is from about 0.01 to about 20 g/10 min. These polymers have agood balance of mechanical properties and processability.

[0061] The most preferred polymers as starting materials for thisinvention are ethylene copolymers with narrow MWD (that is a Mw/Mn ofless than 3.0 most preferably less than about 2.5). These can beproduced using at least one C3-C20 olefin comonomer. Most preferred forcopolymer is C3-C10. About 0.5-5 mole percent comonomer as determined byASTM 5017 is preferred in the starting material. The preferred meltindex of the starting material depends on applications; however, thepreferred melt index for injection molding is from about 0.5 to about 50g/10 min, for thermoforming applications the preferred melt index isfrom about 0.1 to about 20 g/10 min, and for blow molding applications,the preferred melt index is from about 0.01 to about 20 g/10 minmeasured Commercially available polymers in this category are known asTAFMER polymer commercially available from Mitsui PetrochemicalIndustries, EXACT polymer commercially available from Exxon ChemicalCompany, AFFINITY polyolefin plastomer commercially available from TheDow Chemical Company, ENGAGE polyolefin elastomer commercially availablefrom DuPont-Dow Elastomers, and the like. For thermoplastic applicationssuch as film and injection molding, the most preferred comonomer contentis between about 3-25 weight percent. For elastomeric applications, thepreferred comonomer content is between about 20-40 weight percent. Themost preferred terpolymer is an EPDM such as NORDEL ethylene/propyleneldiene polymer commercially available from DuPont-Dow Elastomers.

[0062] The melt index is measured according to ASTM D-1238 condition190° C./2.16 Kg (formerly known as Condition E).

[0063] In one preferred embodiment the polymer includes at least oneethylene/styrene interpolymer. The interpolymers employed in the presentinvention include, but are not limited to, substantially randominterpolymers prepared by polymerizing one or more α-olefin monomerswith one or more vinyl aromatic monomers and/or one or more hinderedaliphatic or cycloaliphatic vinyl monomers, and optionally with otherpolymerizable ethylenically unsaturated monomer(s).

[0064] Suitable α-olefin monomers include for example, α-olefin monomerscontaining from 2 to about 20, preferably from 2 to about 12, morepreferably from 2 to about 8 carbon atoms Preferred such monomersinclude ethylene, propylene, butene-1, 4-methyl-1-pentene, hexene-1 andoctene-1. Most preferred are ethylene or a combination of ethylene withC2-8 α-olefins. These α-olefins do not contain an aromatic moiety.

[0065] Suitable vinyl aromatic monomers which can be employed to preparethe interpolymers employed include, for example, those represented bythe following formula:

[0066] wherein R1 is selected from the group of radicals consisting ofhydrogen and alkyl radicals containing from 1 to about 4 carbon atoms,preferably hydrogen or methyl; each R2 is independently selected fromthe group of radicals consisting of hydrogen and alkyl radicalscontaining from 1 to about 4 carbon atoms, preferably hydrogen ormethyl; Ar is a phenyl group or a phenyl group substituted with from 1to 5 substituents selected from the group consisting of halo,C1-4-alkyl, and C1-4-haloalkyl; and n has a value from zero to about 6,preferably from zero to 2, most preferably zero. Exemplary vinylaromatic monomers include styrene, vinyl toluene, α-methylstyrene,t-butyl styrene, chlorostyrene, including all isomers of thesecompounds, and the like. Particularly suitable such monomers includestyrene and lower alkyl- or halogen-substituted derivatives thereof.Preferred monomers include styrene, a-methyl styrene, the loweralkyl-(C1-C4) or phenyl-ring substituted derivatives of styrene, such asfor example, ortho-, meta-, and para-methylstyrene, the ring halogenatedstyrenes, para-vinyl toluene or mixtures thereof, and the like. A morepreferred aromatic vinyl monomer is styrene.

[0067] By the term “hindered aliphatic or cycloaliphatic vinyl orvinylidene compounds”, it is meant addition polymerizable vinyl orvinylidene monomers corresponding to the formula:

[0068] wherein Al is a sterically bulky, aliphatic or cycloaliphaticsubstituent of up to 20 carbons, R1 is selected from the group ofradicals consisting of hydrogen and alkyl radicals containing from 1 toabout 4 carbon atoms, preferably hydrogen or methyl; each R2 isindependently selected from the group of radicals consisting of hydrogenand alkyl radicals containing from 1 to about 4 carbon atoms, preferablyhydrogen or methyl; or alternatively R¹ and A¹ together form a ringsystem. By the term “sterically bulky” is meant that the monomer bearingthis substituent is normally incapable of addition polymerization bystandard Ziegler-Natta polymerization catalysts at a rate comparablewith ethylene polymerizations. Preferred aliphatic or cycloaliphaticvinyl or vinylidene monomers are those in which one of the carbon atomsbearing ethylenic unsaturation is tertiary or quaternary substitutedExamples of such substituents include cyclic aliphatic groups such ascyclohexyl, cyclohexenyl, cyclooctenyl, or ring alkyl or arylsubstituted derivatives thereof, tert-butyl, norbornyl, and the like.Most preferred hindered aliphatic or cycloaliphatic vinyl or vinylidenecompounds are the various isomeric vinyl- ring substituted derivativesof cyclohexene and substituted cyclohexenes, and5-ethylidene-2-norbornene. Especially suitable are 1-, 3-, and4-vinylcyclohexene.

[0069] Other optional polymerizable ethylenically unsaturated monomer(s)include strained ring olefins such as norbornene and C1-10 alkyl orC6-10 aryl substituted norbornenes, with an exemplary interpolymer beingethylene/styrene/norbornene.

[0070] The number average molecular weight (Mn) of the polymers andinterpolymers is usually greater than about 5,000, preferably from about20,000 to about 1,000,000, more preferably from about 50,000 to about500,000.

[0071] Polymerizations and unreacted monomer removal at temperaturesabove the autopolymerization temperature of the respective monomers mayresult in formation of some amounts of homopolymer polymerizationproducts resulting from free radical polymerization. For example, whilepreparing the substantially random interpolymer, an amount of atacticvinyl aromatic homopolymer may be formed due to homopolymerization ofthe vinyl aromatic monomer at elevated temperatures. The presence ofvinyl aromatic homopolymer, in general, is not detrimental for thepurposes of the present invention and can be tolerated. The vinylaromatic homopolymer may be separated from the interpolymer, if desired,by extraction techniques such as selective precipitation from solutionwith a non solvent for either the interpolymer or the vinyl aromatichomopolymer. For the purpose of the present invention it is preferredthat no more than 20 weight percent, preferably less-than 15 weightpercent based on the total weight of the interpolymers of vinyl aromatichomopolymer is present.

[0072] The substantially random interpolymers are prepared bypolymerizing a mixture of polymerizable monomers in the presence ofmetallocene or constrained geometry catalysts in the presence of variouscocatalysts as described in EP-A-0,416,815 by James C. Stevens et al.and U.S. Pat. No. 5,703,187 by Francis J. Timmers which are incorporatedherein by reference in their entireties. Preferred operating conditionsfor such polymerization reactions are pressures from atmospheric up to3,000 atmospheres and temperatures from −30° C. to 200° C.

[0073] Examples of suitable catalysts and methods for preparing thesubstantially random interpolymers are disclosed in U.S. applicationSer. No. 07/702,475 filed May 20, 1991 corresponding to EP-A-514,828;U.S. application Ser. No. 07/876,268, (C-39819-A) filed May 1, 1992corresponding to EP-A-520,732; U.S. application Ser. No. 08/241,523,(C-41350-B) filed May 12, 1994; U.S. application Ser. No.60/034,819(C-42890), filed Dec. 19, 1996; as well as U.S. Pat. Nos.5,055,438; 5,057,475; 5,096,867; 5,064,802; 5,132,380; 5,189,192;5,321,106; 5,347,024; 5,350,723; 5,374,696; 5,399,635; 5,703,187;5,556,928 and 5,721,185 all of which patents and applications areincorporated herein by reference in their entireties.

[0074] Another, alternative, preferred embodiment involves the use ofpolyolefin-carbon monoxide (CO) copolymers such as ethylene-carbonmonoxide copolymers, propylene-carbon monoxide, andethylene-propylene-carbon monoxide. Such polymers are commerciallyavailable from The Dow Chemical Company (generally CO content less thanabout 2 weight percent) and Shell Oil Company (generally higher amountsof CO). Alternatively, they are prepared by means within the skill inthe art such as that disclosed U.S. Pat. Nos. 3,835,123; 3,984,388;4,970294; 5,554,777 and 5,565,547; which are incorporated herein byreference in their entireties.

[0075] For the purposes of rheology modification or coupling, thepolymer is reacted with a polyfunctional compound capable of insertionreactions into C—H bonds. Such polyfunctional compounds have at leasttwo, preferably 2, functional groups capable of C—H insertion reactions.Those skilled in the art are familiar with C—H insertion reactions andfunctional groups capable of such reactions. For instance, carbenes asgenerated from diazo compounds, as cited in Mathur, N. C.; Snow, M. S.;Young, K. M., and Pincock, J. A.; Tetrahedron, (1985), 41(8), pages1509-1516, and nitrenes as generated from azides, as cited inAbramovitch, R. A.,; Chellathurai, T.; Holcomb, W. D; McMaster, I. T.;and Vanderpool, D. P.; J. Ora. Chem., (1977), 42(17), 2920-6, andAbramovitch, R. A., Knaus, G. N., J. Org. Chem., (1975), 40(7), 883-9.

[0076] Compounds having at least two functional groups capable of C—Hinsertion under reaction conditions are referred to herein as couplingagents. Such coupling agents include alkyl and aryl azides (R—N₃), acylazides (R—C(O)N₃), azidoformates (R—O—C(O)—N₃), phosphoryl azides((RO)₂—(PO)—N₃), phosphinic azides (R₂—P(O)—N₃) and silyl azides(R₃—Si—N₃).

[0077] Polyfunctional compounds capable of insertions into C—H bondsalso include poly(sulfonyl azide)s. The poly(sulfonyl azide) is anycompound having at least two sulfonyl azide groups (—SO₂N₃) reactivewith the polyolefin. Preferably the poly(sulfonyl azide)s have astructure X—R—X wherein each X is SO₂N₃ and R represents anunsubstituted or inertly substituted hydrocarbyl, hydrocarbyl ether orsilicon-containing group, preferably having sufficient carbon, oxygen orsilicon, preferably carbon, atoms to separate the sulfonyl azide groupssufficiently to permit a facile reaction between the polyolefin and thesulfonyl azide, more preferably at least 1, more preferably at least 2,most preferably at least 3 carbon, oxygen or silicon, preferably carbon,atoms between functional groups. While there is no critical limit to thelength of R, each R advantageously has at least one carbon or siliconatom between X's and preferably has less than about 50, more preferablyless than about 30, most preferably less than about 20 carbon, oxygen orsilicon atoms. Within these limits, larger is better for reasonsincluding thermal and shock stability. When R is straight-chain alkylhydrocarbon, there are preferably less than 4 carbon atoms between thesulfonyl azide groups to reduce the propensity of the nitrene to bendback and react with itself. Silicon containing groups include silanesand siloxanes, preferably siloxanes. The term inertly substituted refersto substitution with atoms or groups which do not undesirably interferewith the desired reaction(s) or desired properties of the resultingcoupled polymers. Such groups include fluorine, aliphatic or aromaticether, siloxane as well as sulfonyl azide groups when more than twopolyolefin chains are to be joined. Suitable structures include R asaryl, alkyl, aryl alkaryl, arylalkyl silane, siloxane or heterocyclic,groups and other groups which are inert and separate the sulfonyl azidegroups as described More preferably R includes at least one aryl groupbetween the sulfonyl groups, most preferably at least two aryl groups(such as when R is 4,4′ diphenylether or 4,4′-biphenyl). When R is onearyl group, it is preferred that the group have more than one ring, asin the case of naphthylene bis(sulfonyl azides). Poly(sulfonyl)azidesinclude such compounds as 1,5-pentane bis(sulfonlazide), 1,8-octanebis(sulfonyl azide), 1,10-decane bis(sulfonyl azide), 1,10-octadecanebis(sulfonyl azide), 1-octyl-2,4,6-benzene tris(sulfonyl azide),4,4′-diphenyl ether bis(sulfonyl azide),1,6-bis(4′-sulfonazidophenyl)hexane, 2,7-naphthalene bis(sulfonylazide), and mixed sulfonyl azides of chlorinated aliphatic hydrocarbonscontaining an average of from 1 to 8 chlorine atoms and from about 2 to5 sulfonyl azide groups per molecule, and mixtures thereof. Preferredpoly(sulfonyl azide)s include oxy-bis(4-sulfonylazidobenzene),2,7naphthalene bis(sulfonyl azido), 4,4′-bis(sulfonyl azido)biphenyl,4,4′-diphenyl ether bis(sulfonyl azide) and bis(4-sulfonylazidophenyl)methane, and mixtures thereof.

[0078] Sulfonyl azides are conveniently prepared by the reaction ofsodium azide with the corresponding sulfonyl chloride, althoughoxidation of sulfonyl hydazines with various reagents (nitrous acid,dinitrogen tetroxide, nitrosonium tetrafluoroborate) has been used.

[0079] Polyfunctional compounds capable of insertions into C—H bondsalso include carbene-forming compounds such as salts of alkyl and arylhydrazones and diazo compounds, and nitrene-forming compounds such asalkyl and aryl azides (R—N₃), acyl azides (R—C(O)N₃), azidoformates(R—O—C(O)—N₃), sulfonyl azides (R—SO₂—N₃), phosphoryl azides((RO)₂—(PO)—N₃), phosphinic azides (R₂—P(O)—N₃) and silyl azides(R₃—Si—N₃). Some of the coupling agents of the invention are preferredbecause of their propensity to form a greater abundance ofcarbon-hydrogen insertion products. Such compounds as the salts ofhydrazones, diazo compounds, azidoformates, sulfonyl azides, phosphorylazides, and silyl azides are preferred because they form stablesinglet-state electron products (carbenes and nitrenes) which carry outefficient carbon-hydrogen insertion reactions, rather thansubstantially 1) rearranging via such mechanisms as the Curtius-typerearrangement, as is the case with acyl azides and phosphinic azides, or2) rapidly converting to the triplet-state electron configuration whichpreferentially undergoes hydrogen atom abstraction reactions, which isthe case with alkyl and aryl azides. Also, selection from among thepreferred coupling agents is conveniently possible because of thedifferences in the temperatures at which the different classes ofcoupling agents are converted to the active carbene or nitrene productsFor example, those skilled in the art will recognize that carbenes areformed from diazo compounds efficiently at temperatures less than 100°C., while salts of hydrazones, azidoformates and the sulfonyl azidecompounds react at a convenient rate at temperatures above 100° C., upto temperatures of about 200° C. (By convenient rates it is meant thatthe compounds react at a rate that is fast enough to make commercialprocessing possible, while reacting slowly enough to allow adequatemixing and compounding to result in a final product with the couplingagent adequately dispersed and located substantially in the desiredposition in the final product. Such location and dispersion may bedifferent from product to product depending on the desired properties ofthe final product.) Phosphoryl azides may be reacted at temperatures inexcess of 180° C. up to about 300° C., while silyl azides reactpreferentially at temperatures of from about 250° C. to 400° C.

[0080] To modify rheology, also referred to herein as “to couple,” thepoly(sulfonyl azide) is used in a rheology modifying amount, that is anamount effective to increase the low-shear viscosity (at 0.1 rad/sec) ofthe polymer preferably at least about 5 percent as compared with thestarting material polymer, but less than a crosslinking amount, that isan amount sufficient to result in at least about 10 weight percent gelas measured by ASTM D2765-procedure A. While those skilled in the artwill recognize that the amount of azide sufficient to increase the lowshear viscosity and result in less than about 10 weight percent gel willdepend on molecular weight of the azide used and polymer the amount ispreferably less than about 5 percent, more preferably less than about 2percent, most preferably less than about 1 weight percent poly(sulfonylazide) based on total weight of polymer when the poly(sulfonyl azide)has a molecular weight of from about 200 to about 2000. To achievemeasurable rheology modification, the amount of poly(sulfonyl azide) ispreferably at least about 0.01 weight percent, more preferably at leastabout 0.05 weight percent, most preferably at least about 0.10 weightpercent based on total polymer.

[0081] For rheology modification, the sulfonyl azide is admixed with thepolymer and heated to at least the decomposition temperature of thesulfonyl azide. By decomposition temperature of the azide it is meantthat temperature at which the azide converts to the sulfonyl nitrene,eliminating nitrogen and heat in the process, as determined bydifferential scanning calorimetry (DSC). The poly(sulfonyl azide)beginsto react at a kinetically significant rate (convenient for use in thepractice of the invention) at temperatures of about 130° C. and isalmost completely reacted at about 160° C. in a DSC (scanning at 10°C./min). ARC (scanning at 2° C./ hr) shows onset of decomposition isabout 100° C. Extent of reaction is a function of time and temperature.At the low levels of azide used in the practice of the invention, theoptimal properties are not reached until the azide is essentially fullyreacted. Temperatures for use in the practice of the invention are alsodetermined by the softening or melt temperatures of the polymer startingmaterials. For these reasons, the temperature is advantageously greaterthan about 90° C., preferably greater than about 120° C., morepreferably greater than about 150° C., most preferably greater than 180°C.

[0082] Preferred times at the desired decomposition temperatures aretimes that are sufficient to result in reaction of the coupling agentwith the polymer(s) without undesirable thermal degradation of thepolymer matrix. Preferred reaction times in terms of the half life ofthe coupling agent, that is the time required for about half of theagent to be reacted at a preselected temperature, which half life is.determinable by DSC is about 5 half lives of the coupling agent. In thecase of a bis(sulfonyl azide), for instance, the reaction time ispreferably at least about 4 minutes at 200° C.

[0083] Admixing of the polymer and coupling agent is convenientlyaccomplished by any means within the skill in the art. Desireddistribution is different in many cases, depending on what Theologicalproperties are to be modified In a homopolymer it is desirable to haveas homogeneous a distribution as possible, preferably achievingsolubility of the azide in the polymer melt. In a blend it is desirableto have low solubility in one or more of the polymer matrices such thatthe azide is preferentially in one or the ocher phase, or predominantlyin the interfacial region between the two phases.

[0084] It has been found that the process of combining the polymer andcoupling agent are important to achieving the desired result of avoidinglocalized gels, dark specks or other indications of nonuniformdistribution of coupling agent and, especially, of avoiding thedisadvantages of solvent handling and removal inherent in use ofsolvents for the coupling agent. After practice of the present inventionthere are preferably less than about 10 percent, more preferably lessthan about 5 percent, most preferably less than about 2 weight percentgels present as determined by xylene solubility.

[0085] Preferred processes include at least one of (a) introducing, e.g.by injection, a coupling agent in liquid form, in a slurry or otheradmixture of coupling agent in a liquid which does not require removalfrom the polymer, hereinafter diluent, into a device containing polymer,preferably softened, molten or melted polymer, but alternatively inparticulate form, more preferably in melt processing equipment; or (b)forming a first admixture of a first amount of a first polymer and acoupling agent, advantageously at a temperature less than about thedecomposition temperature of the coupling agent, preferably by meltblending, and then forming a second admixture of the first admixturewith a second amount of a second polymer (for example a concentrate of acoupling agent admixed with at least one polymer and optionally otheradditives, is conveniently admixed into a second polymer or combinationthereof optionally with other additives, to modify the secondpolymer(s)). Hereinafter, in both methods the admixture containingcoupling agent (with either the diluent or the first polymer or acombination thereof) is referred to as a “concentrate” Of the two steps(b) is preferred. For example, process (b) is conveniently used to makea concentrate with a first polymer composition having a lower meltingtemperature, advantageously at a temperature below the decompositiontemperature of the coupling agent, and the concentrate is melt blendedinto a second polymer composition having a higher melting temperature tocomplete the coupling reaction. Concentrates are especially preferredwhen temperatures are sufficiently high to result in loss of couplingagent by evaporation or decomposition not leading to reaction with thepolymer, or other conditions would result that effect. Alternatively,some coupling occurs during the blending of the first polymer andcoupling agent, but some of the coupling agent remains unreacted untilthe concentrate is blended into the second polymer composition. Eachpolymer or polymer composition includes at least one homopolymer,copolymer, terpolymer, or interpolymer and optionally includes additiveswithin the skill in the art.

[0086] In (a), the diluent is a compound which does not require removalfrom the resulting polymer composition, that is a compound which doesnot interfere undesirably with subsequent process steps applied to theresulting polymer composition. By does not interfere undesirably, ismeant that while those skilled in the art may recognize a slight effectfrom its presence, e.g. a slower subsequent step, that effect is not sodisadvantageous as to dissuade one from using the diluent. To that endthe diluent differs from a solvent in being non-volatile (no more than 5percent vapor pressure) at temperatures encountered in subsequentprocess steps, including decomposition of the coupling agent (that is upto about 260° C.) such that increased pressure or other means is notrequired for its control in subsequent steps. The diluent is preferablya liquid at room temperature or low melting (that is melting point belowabout 50° C.) solid at room temperature. Diluents are preferablynon-polar compounds such as mineral oils in which the coupling agent issufficiently miscible to disperse the coupling agent in a polymer. Suchdiluents include mineral oil; aliphatic carboxylic acid esterspreferably of at least about 12 carbon atoms, more preferably of lessthan about 200 carbon atoms; parafinic, naphthenic, or aromatic oilhaving a boiling point greater than about 230° C., but preferably liquidat 20° C., preferably mineral oil. In (b), the first polymer ispreferably low melting, that is has a melting point below about 110° C.or a melt index (I2) of at least about 0.25 g/10 min., preferably 1 g/10min or greater. Such polymers include, for instance, ethylene alphaolefin copolymers, especially where the alpha olefins are of 3 to 20carbons, have a density range of at least about 0.855 g/cc, preferablyup to about 0.955 g/cc, more preferably up to about 0.890 g/cc,preferably with an melt index (I2) of at least about 0.5 g/10 min, morepreferably at least about 5, and preferably less than about 2000 g/10min, more preferably less than about 1000 g/10 min., most preferablyless than about 100 g/10 min Similarly, ethylene acrylic acid, ethylenevinyl acetate and ethylene/styrene interpolymers preferably with amelting temperature of less than about 150° C., more preferably lessthan about 130° C.

[0087] The concentrate is conveniently blended with polymer in any form,for instance molten, powdered, pelleted and the like, preferably dryblended with pelleted polymer or injection of molten concentrate intomolten polymer, advantageously molten polymer directly from or in apolymerization reactor.

[0088] Optionally, the concentrate is formed on the surface of a polymerto be coupled according to the practice of the invention. For instance,a diluent is coated on a polymer, conveniently a comminuted polymer,preferably pelleted or powdered, more preferably pelleted, for instanceby stirring or tumbling particulate polymer with a diluent, forinstance, mineral oil. Then the coupling agent is admixed with thediluent coated on the polymer Thus, steps of the process of theinvention suitably occur in any order that results in a sufficientlyuniform admixture of concentrate and polymer(s) to substantially avoidevidence of localized concentrations of coupling agent.

[0089] The term “melt processing” is used to mean any process in whichthe polymer is softened or melted, such as extrusion, pelletizing,molding, thermoforming, film blowing, compounding in polymer melt form,fiber spinning, and the like.

[0090] Preferably, a substantially uniform admixture of coupling agentand polymer is formed before exposure to conditions in which chaincoupling takes place. A substantially uniform admixture is one in whichthe distribution of coupling agent in the polymer is sufficientlyhomogeneous to be evidenced by a polymer having a melt viscosity aftertreatment according to the practice of the invention either higher atlow angular frequency (e.g. 0.1 rad/sec) or lower at higher angularfrequency (eg. 100 rad/sec) than that of the same polymer which has notbeen treated with the coupling agent but has been subjected to the sameshear and thermal history. Thus, preferably, in the practice of theinvention, decomposition of the coupling agent occurs after mixingsufficient to result in a substantially uniform admixture of couplingagent and polymer. This mixing is preferably attained with the polymerin a molten or melted state, that is above the crystalline melttemperature, or in a dissolved or finely dispersed condition rather thanin a solid mass or particulate form. The molten or melted form is morepreferred to insure homogeniety rather than localized concentrations atthe surface.

[0091] Any equipment is suitably used, preferably equipment whichprovides sufficient mixing and temperature control in the sameequipment, but advantageously practice of the invention takes place insuch devices as an extruder or a static polymer mixing device such as aBrabender blender. The term extruder is used for its broadest meaning toinclude such devices as a device which extrudes pellets or pelletizer.Conveniently, when there is a melt extrusion step between production ofthe polymer and its use, at least one step of the process of theinvention takes place in the melt extrusion step.

[0092] In a preferred embodiment the process of the present inventiontakes place in a single vessel, that is mixing of the coupling agent andpolymer takes place in the same vessel as heating to the decompositiontemperature of the coupling agent. The vessel is preferably a twin-screwextruder, but is also advantageously a single-screw extruder or a batchmixer. The reaction vessel more preferably has at least two zones ofdifferent temperatures into which a reaction mixture would pass, thefirst zone advantageously being at a temperature at least thecrystalline melt temperature or the softening temperature of thepolymer(s) and preferably less than the decomposition temperature of thecoupling agents and the second zone being at a temperature sufficientfor decomposition of the coupling agent. The first zone is preferably ata temperature sufficiently high to soften the polymer and allow it tocombine with the coupling agent through distributive mixing to asubstantially uniform admixture.

[0093] To avoid the extra step and resultant cost of re-extrusion and toensure that the coupling agent is well blended into the polymer, inalternative preferred embodiments it is preferred that the couplingagent be added to the post-reactor area of a polymer processing plant.For example, in a slurry process of producing polyethylene, the couplingagent is added in either powder or liquid form to the powderedpolyethylene after the solvent is removed by decantation and prior tothe drying and densification extrusion process. In an alternativeembodiment, when polymers are prepared, in a gas phase process, thecoupling agent is preferably added in either powder or liquid form tothe powdered polyethylene before the densification extrusion. In analternative embodiment when a polymer is made in a solution process, thecoupling agent is preferably added to the polymer solution or to adevolatilized polymer melt prior to the densification extrusion process.

[0094] Practice of the process of the invention to rheology modifypolymers yields rheology modified or chain coupled polymers, that is thepolymers which have sulfonamide, amine, alkyl-substituted oraryl-substituted carboxamide, alkyl-substituted or aryl-substitutedphosphoramide, alkyl-substituted or aryl-substituted methylene couplingbetween different polymer chains. Resulting compounds advantageouslyshow higher low shear viscosity than the original polymer due tocoupling of long polymer chains to polymer backbones. Broad molecularweight distribution polymers (polydispersity (P.D.) of 3.5 and greater)and gel levels less than 10 percent as determined by xylene extractionshow less improvement than the dramatic effect noted in narrow MWDpolymer (P.D.=2.0) with gel less than 10 percent as determined by xyleneextraction.

[0095] Rheology modification leads to polymers which have controlledTheological properties, specifically improved melt strength as evidencedby increased low shear viscosity, better ability to hold oil, improvedscratch and mar resistance, improved tackiness, improved green strength(melt), higher orientation in high shear and high extensional processessuch as injection molding, film extrusion (blown and cast), calendaring,rotomolding, fiber production, profile extrusion, foams, and wire &cable insulation as measured by tan delta as described hereinafterelasticity by viscosity at 0.1 rad/sec and 100 rad/sec, respectively Itis also believed that this process can be used to produce dispersionshaving improved properties of higher low shear viscosity than theunmodified polymer as measured by DMS.

[0096] Rheology modified polymers are useful as large blow moldedarticles due to the higher low shear viscosity than unmodified polymerand the maintenance of the high shear viscosity for processability asindicated by high shear viscosity, foams for stable cell structure asmeasured by low shear viscosity, blown film for better bubble stabilityas measured by low shear viscosity, fibers for better spinnability asmeasured by high shear viscosity, cable and wire insulation for greenstrength to avoid sagging or deformation of the polymer on the wire asmeasured by low shear viscosity which are aspects of the invention.

[0097] Polymers rheology modified according to the practice of theinvention are superior to the corresponding unmodified polymer startingmaterials for these applications due to the elevation of viscosity, ofpreferably at least about 5 percent at low shear rates (0.1 rad/sec),sufficiently high melt strengths to avoid deformation during thermalprocessing (e.g. to avoid sag during thermoforming) or to achieve bubblestrength during blow molding, and sufficiently low high shear rateviscosities to facilitate molding and extrusion. These Theologicalattributes enable faster filling of injection molds at high rates thanthe unmodified starting materials, the setup of foams (stable cellstructure) as indicated by formation of lower density closed cell foam,preferably with higher tensile strength, insulation properties, and/orcompression set than attained in the use of coupling or rheologymodification using coupling agents which generate free radicals, becauseof high melt viscosity Advantageously toughness and tensile strength ofthe starting material is maintained.

[0098] Polymers resulting from the practice of the invention aredifferent from those resulting from practice of prior art processes asshown in CA 797,917. The polymers of the present invention show improvedmelt elasticity, that is higher tan delta as measured by DMS, betterdrawability, that is higher melt strength as measured by melt tension,less swelling as measured by blow molding die swell, and less shrinkageas measured by mold shrinkage than the unmodified polymer and the broadMWD (greater than 3.0 Mw/Mn). counterpart in thermoforming and largepart blow molding.

[0099] There are many types of molding operations which can be used toform useful fabricated articles or parts from the formulations disclosedherein, including various injection molding processes (e.g., thatdescribed in Modern Plastics Encyclopedia/89, Mid October 1988 Issue,Volume 65, Number 11, pp. 264-268, “Introduction to Injection Molding”and on pp. 270-271, “Injection Molding Thermoplastics”, the disclosuresof which are incorporated herein by reference) and blow moldingprocesses (e.g., that described in Modern Plastics Encyclopedia/89, MidOctober 1988 Issue, Volume 65, Number 11, pp. 217-218, “Extrusion-BlowMolding”, the disclosure of which is incorporated herein by reference),profile extrusion, calendering, pultrusion and the like.

[0100] The rheology-modified ethylene polymers, processes for makingthem, and intermediates for making them of this invention are useful inthe automotive area, industrial goods, building and construction,electrical (e.g., wire and cable coatings/insulation) and tire products.Some of the fabricated articles include automotive hoses, single plyroofing, and wire and cable voltage insulation and jackets.

[0101] Film and film structures particularly benefit from this inventionand can be made using conventional hot blown film fabrication techniquesor other biaxial orientation processes such as tenter frames or doublebubble processes. Conventional hot blown film processes are described,for example, in The Encyclopedia of Chemical Technology, Kirk-Othmer,Third Edition, John Wiley & Sons, New York, 1981, vol. 16, pp. 416-417and Vol. 18, pp. 191-192. Biaxial orientation film manufacturing processsuch as described in a “double bubble” process as in U.S. Pat. No.3,456,044 (Pahlke), and the processes described in U.S. Pat. No.4,352,849 (Mueller), U.S. Pat. No. 4,597,920 (Golike), U.S. Pat. No.4,820,557 (Warren), U.S. Pat. No. 4,837,084 (Warren), U.S. Pat. No.4,865,902 (Golike et al.), U.S. Pat. No. 4,927,708 (Herran et al.), U.S.Pat. No. 4,952,451 (Mueller), U.S. Pat. No. 4,963,419 (Lustig et al.),and U.S. Pat. No. 5,059,481 (Lustig et al.), can also be used to makefilm structures from the novel compostions described herein. The filmstructures can also be made as described in a tenter-frame technique,such as that used for oriented polypropylene.

[0102] Other multi-layer film manufacturing techniques for foodpackaging applications are described in Packaging Foods With Plastics,by Wilmer A. Jenkins and James P. Harrington (1991), pp. 19-27, and in“Coextrusion Basics” by Thomas I. Butler, Film Extrusion Manual:Process, Materials, Properties pp. 31-80 (published by the TAPPI Press(1992)).

[0103] The films may be monolayer or multilayer films. The film madeusing this invention can also be coextruded with the other layer(s) orthe film can be laminated onto another layer(s) in a secondaryoperation, such as that described in Packaging Foods With Plastics, byWilmer A. Jenkins and James P. Harrington (1991) or that described in“Coextrusion For Barrier Packaging” by W. J. Schrenk and C. R. Finch,Society of Plastics Engineers RETEC Proceedings, Jun. 15-17 (1981), pp.211-229. If a monolayer film is produced via tubular film (i.e., blownfilm techniques) or flat die (i.e., cast film) as described by K. R.Osborn and W. A. Jenkins in “Plastic Films, Technology and PackagingApplications” (Technomic Publishing Co., Inc., 1992), the disclosure ofwhich is incorporated herein by reference, then the film must go throughan additional post-extrusion step of adhesive or extrusion lamination toother packaging material layers to form a multilayer structure. If thefilm is a coextrusion of two or more layers (also described by Osbornand Jenkins), the film may still be laminated to additional layers ofpackaging materials, depending on the other physical requirements of thefinal film. “Laminations vs Coextrusion” by D. Dumbleton (ConvertingMagazine (September 1992), also discusses lamination versus coextrusion.Monolayer and coextruded films can also go through other post extrusiontechniques, such as a biaxial orientation process.

[0104] Extrusion coating is yet another technique for producingmultilayer film structures using the novel compositions describedherein. The novel compositions comprise at least one layer of the filmstructure. Similar to cast film, extrusion coating is a flat dietechnique. A sealant can be extrusion coated onto a substrate either inthe form of a monolayer or a coextruded extrudate.

[0105] Generally for a multilayer film structure, the novel compositionsdescribed herein comprise at least one layer of the total multilayerfilm structure. Other layers of the multilayer structure include but arenot limited to barrier layers, and/or tie layers, and/or structurallayers. Various materials can be used for these layers, with some ofthem being used as more than one layer in the same film structure Someof these materials include: foil, nylon, echylene/vinyl alcohol (EVOH)copolymers, polyvinylidene chloride (PVDC), polyethylene terethphalate(PET), oriented polypropylene (OPP), ethylene/vinyl acetate (EVA)copolymers, ethylene/acrylic acid (BAA) copolymers, ethylene/methacrylicacid (EMAA) copolymers, LLDPE, HDPE, LDPE, nylon, graft adhesivepolymers (e.g., maleic anhydride grafted polyethylene), and paper.Generally, the multilayer film structures comprise from 2 to 7 layers.

[0106] Such articles comprising the rheology-modified polymer of thisinvention may be made by melt processing the rheology-modified polymeraccording to this invention. That process may include processing pelletsor granules of polymer which have been rheology-modified according tothis invention. In a preferred embodiment, the pellets or granules aresubstantially free of unreacted crosslinking agent when the crosslinkingagent comprises a heat-activated crosslinking agent.

[0107] Such articles may also be made by melt processing an intermediatecomprising a homogeneous polymer which is not substantially free ofunreacted crosslinking agent. Such intermediates are preferably treatedwith a crosslinking agent, but are not subjected to subsequent meltprocessing until the polymer is melted to make the article. Thecrosslinking agent may be either radiation or a heat-activatedcrosslinking agent.

[0108] The rheology-modified polymers and intermediates used to makerheology-modified polymers may be used alone or in combination with oneor more additional polymers in a polymer blend. When additional polymersare present, they may be selected from any of the modified or unmodifiedhomogeneous polymers described above for this invention and/or anymodified or unmodified heterogeneous polymers.

[0109] The heterogeneous polyethylenes that may be combined with therheology-modified polymers according to this invention fall into twobroad categories, those prepared with a free radical initiator at hightemperature and high pressure, and those prepared with a coordinationcatalyst at high temperature and relatively low pressure The former aregenerally known as low density polyethylenes (LDPE) and arecharacterized by branched chains of polymerized monomer units pendantfrom the polymer backbone. LDPE polymers generally have a densitybetween about 0.910 and 0.935 g/cc. Ethylene polymers and copolymersprepared by the use of a coordination catalyst, such as a Ziegler orPhillips catalyst, are generally known as linear polymers because of thesubstantial absence of branch chains of polymerized monomer unitspendant from the backbone. High density polyethylene (HDPE), generallyhaving a density of about 0.941 to about 0.965 g/cc, is typically ahomopolymer of ethylene, and it contains relatively few branch chainsrelative to the various linear copolymers of ethylene and an α-olefin.HDPE is well known, commercially available in various grades, and may beused in this invention.

[0110] Linear copolymers of ethylene and at least one α-olefin of 3 to12 carbon atoms, preferably of 4 to 8 carbon atoms, are also well knownand commercially available. As is well known in the art, the density ofa linear ethylene/α-olefin copolymer is a function of both the length ofthe α-olefin and the amount of such monomer in the copolymer relative tothe amount of ethylene, the greater the length of the α-olefin and thegreater the amount of α-olefin present, the lower the density of thecopolymer. Linear low density polyethylene (LLDPE) is typically acopolymer of ethylene and an α-olefin of 3 to 12 carbon atoms,preferably 4 to 8 carbon atoms (e.g, 1-butene, 1-octene, etc.), that hassufficient α-olefin content to reduce the density of the copolymer tothat of LDPE. When the copolymer contains even more α-olefin, thedensity will drop below about 0.91 g/cc and these copolymers are knownas ultra low density polyethylene (ULDPE) or very low densitypolyethylene (VLDPE). The densities of these linear polymers generallyrange from about 0.87 to 0.91 g/cc.

[0111] Both the materials made by the free radical catalysts and by thecoordination catalysts are well known in the art, as are their methodsof preparation. Heterogeneous linear ethylene polymers are availablefrom The Dow Chemical Company as Dowlex™ LLDPE and as Attane™ ULDPEresins. Heterogeneous linear ethylene polymers can be prepared via thesolution, slurry or gas phase polymerization of ethylene and one or moreoptional α-olefin comonomers in the presence of a Ziegler Nattacatalyst, by processes such as are disclosed in U.S. Pat. No. 4,076,698to Anderson et al., which is incorporated herein by reference.Preferably, heterogeneous ethylene polymers are typically characterizedas having molecular weight distributions, M_(w)/m_(n), in the range offrom 3.5 to 4.1. Relevant discussions of both of these classes ofmaterials, and their methods of preparation are found in U.S. Pat. No.4,950,541 and the patents to which it refers, all of which areincorporated herein by reference.

[0112] Compositions of the invention and compositions produced bypractice of the invention are particularly useful because of theirsurprising properties. For instance the preferred medium densitypolyethylenes and ethylene copolymers (density about 0.90 g/mL,comonomer content 0.5-5 mole percent) of the invention are particularlyuseful as blown films such as in trash bags, grocery sacks, sealantlayers, tie layers, produce bags, garment bags, shipping sacks, medicalfilms, stretch film, shrink film; agricultural film, construction film,geomembranes, stretch hooders, and the like, preferably trash bags,agricultural film, construction film, and geomembranes. Similarly themedium density preferred embodiments are useful in cast films such asare useful in stretch films, diaper backsheets, industrial wrap, producewrap, meat wrap, consumer wrap, shrink film elastic film and the like,preferably as elastic film. The high density polyethylene (densitygreater than about 0.945 g/ml and preferably MWD less than about 3)preferred embodiments are particularly useful for thermoforming,preferably for use in refrigerator liners, thin walled containers,medical blister packs, modified atmosphere packaging; and in blowmolding to form such articles as oil bottles, pipe, fuel tanks, milkjugs, and trigger bottles. The low density ethylene copolymer preferredembodiments (density less than about 0.89 g/mL and comonomer contentpreferably about 5-25 mole percent) are particularly useful in extrusionsuch as to form wire and cable coatings, tubing, profiles such asgaskets and seals, sheeting, extrusion coatings such as carpet backing,multilayer packaging, tougheners, and impact modifiers for blends ofpolymers, preferably for wire and cable coating, tougheners and impactmodifiers. The low density preferred embodiments are also particularlyuseful for calendaring to form such materials as sheeting, packagingfilms, and non-packaging films; for foams particularly cushionpackaging, toys, building and construction uses, automotive uses, bodyboards, airline seats, floral and craft uses, preferably cushionpackaging, building and construction, automotive uses, and body boards;and for adhesives and sealants, particularly hot melt adhesives,pressure sensitive adhesives (whether applied in solvents or by hotmelt), caulks, and as tackifiers in other compositions.

[0113] Practice of the present invention increases the utility ofethylene polymers, particularly high density polyethylene, and propylenepolymers in the automotive field. With increased melt strength itbecomes possible to produce such automotive articles as fascia, bumperenergy absorbers, bumper beams, door trim panels, door hardwarecartridges, seat backs, seat pans, head rest cores, header trim, headerenergy absorbing (EA) inserts, pillars, instrument panels, instrumentpanel trim, bolsters, glove boxes, doors, consoles, ducts, parcelshelves, hat shelves, load floors, rocker panels, fenders and the likeand combinations thereof using such means as blow molding, injectionmolding, thermoforming, and gas assisted injection molding. Furthermore,such automotive articles as cross car supports, door outer panels, seattrim, and the like and combinations thereof can be produced using suchmeans as blow molding, injection molding, and thermoforming. Sucharticles as roof liners, underbody closeouts (underbody shields),pick-up bed liners, and wheel liners can be conveniently produced bythermoforming; while such articles as fuel filler necks and fuel tankscan be produced using blow molding, roto-molding or injection molding.Injection molding, thermoforming and gas assisted injection molding areuseful for producing door impact beams. Such articles as bumper beams,door impact beams, heater trim, roof liners, ducts, pick-up bed liners,fuel filler necks, fuel transport lines and conductive fuel systems areconveniently produced by extrusion or coextrusion as well Coextrusion isadditionally useful for rocker panels and fenders. Conductive fuelsystems are also optionally roto-molded or blow molded. Roto-molding isalso useful for door EA inserts, seat backs, head rest cores, header EA,instrument panel trim, bolsters, and ducts; while blow molding isadditionally useful for door EA inserts Furthermore, foaming is usefulfor bumper energy absorbers, bumper beams, door trim panels, door EAinserts, seat trim, head rest cores, header trim, roof liners, headerEA, pillars, instrument panel trim, bolsters, and pick-up bed liners.Compression thermoforming, that is thermoforming at a pressure greaterthan about 240 kPa, is useful to produce such articles as bumper beams,cross car supports, door impact beams, door outer panels, door hardwarecartridges, seat backs, seat pans, header trim, roof liners, instrumentpanel trim, bolsters, ducts, parcel shelves, hat shelves, load floors,rocker panels, fenders, underbody closeouts, pick-up bed liners, wheelliners and the like and combinations thereof. Practice of the inventionadvantageously facilitates blow molding, thermoforming and foamingethylene polymers and propylene polymers that without reaction withpoly(sulfonyl azide) would not be conveniently shaped using thosemethods and which have a fractional melt (as measured by the procedureof ASTM-D1238 using 5 kg weight and 109° C.) at least one order ofmagnitude lower than starting material before coupling.

[0114] The following examples are to illustrate this invention and donot limit it. Ratios, parts, and percentages are by weight unlessotherwise stated. Examples (Ex) of the invention are designatednumerically while comparative samples (C.S.) are designatedalphabetically and are not examples of the invention.

[0115] Test Methods

[0116] A Rheometrics, Inc. RMS-800 dynamic mechanical spectrometer with25 mm diameter parallel plates was used to determine the dynamicTheological data. A frequency sweep with five logarithmically spacedpoints per decade was run from 0.1 to 100 rad/s at 190 ° C. The strainwas determined to be within the linear viscoelastic regime by performinga strain sweep at 0.1 rad/s and 190° C., by strain sweep from 2 to 30percent strain in 2 percent steps to determine the minimum requiredstrain to produce torques within the specification of the transducer;another strain sweep at 100 rad/s and 190 ° C. was used to determine themaximum strain before nonlinearity occurred according to the proceduredisclosed by J. M. Dealy and K. F. Wissbrun, “Melt Rheology and Its Rolein Plastics Processing”, Van Nostrand, New York (1990). All testing wasperformed in a nitrogen purge to minimize oxidative degradation.

[0117] A Perkin Elmer model TMA 7 thermomechanical analyzer was used tomeasure the upper service temperature. Probe force of 102 g and heatingrate of 5° C./min were used. Each test specimen was a disk withthickness of about 2 mm and diameter, prepared by compression molding at205° C. and air-cooling to room temperature.

[0118] Xylene Extraction to determine gel content was performed byweighing out 1 gram samples of polymer. The samples are transferred to amesh basket which is then placed in boiling xylene for 12 hours. After12 hours, the sample baskets are removed and placed in a vacuum oven at150° C. and 28 in. of Hg vacuum for 12 hours. After 12 hours, thesamples are removed, allowed to cool to room temperature over a 1 hourperiod, and then weighed The results are reported as percent polymerextracted. Percent extracted=(initial weight-final weight)/initialweight according to ASTM D-2765 Procedure “A”

[0119] Samples were prepared using either a HaakeBuchler Rheomix 600mixer with roller style blades, attached to a HaakeBuchler Rheocord 9000Torque rheometer, or using a Brabender mixer (Type R.E.E. No. A-19/S.B)with a 50 g mixing bowl

[0120] All instruments were used according to manufacturer's directions.

EXAMPLES 1 AND 2 AND COMPARATIVE SAMPLE A: FILMS

[0121] The resin used in Examples 1 and 2 is an ethylene-octenecopolymer with Mw/Mn=3.26, Mw=71100, having a melt index of 6 (g/10min.), and a density of 0.919 g/cc commercially available from The DowChemical Company under the trade designation DOWLEX 2035 polyethylenereferred to hereinafter by the trade designation.

[0122] Resin Preparation for Examples 1 and 2

[0123] One hundred pounds (45.4 kg) of the DOWLEX™ 2035 polyethyleneresin pellets (containing 200 ppm hindered polyphenolic stabilizercommercially available from Ciba Geigy Corporation under the tradedesignation Irganox 1010 stabilizer and 750 ppm synthetic dihydrotalcitecommercially available from Kyowa under the trade designation DHT 4Astabilizer) were tumble blended with 200 ml of mineral oil for 30minutes in a 55 gallon (207.9 liter) fiber drum (with liner) at about 6rotations per minute. A total of 54.4 g (corresponding to 1200 ppm) of4,4′-oxybis(benzenesulfonyl azide) (hereinafter BSA) was added to theabove mixture and tumble blended for 2 hours to ensure adequate coatingof the pellets. The above procedure was repeated three times such that300 pounds (136.2 kg) of coated resin were produced. After the dryblending, this admixture of coupling agent and resin was fed into a twinscrew extruder having a screw diameter of 30 cm commercially availablefrom Werner Pfleiderer Corporation under the trade designation ZSK-30twin screw extruder. The extruder measured temperature was 130° C., 175°C., 215° C., 221° C., and 221° C. for zones 1, 2, 3, 4, and 5,respectively. The temperature was measured using thermocouples thatcontact the metal. The distances of the thermocouples from the center ofthe feed zone are about 8.8, 38.8, 56.2, 66.3, 78.8, and 88.8 cm fromthe feed to the discharge (die) of the extruder for Zones 1, 2, 3, 4,and 5, respectively. The melt temperature and die temperatures were 230°C. and 220° C., respectively. The melt-extruded resin ran through awater cooling bath (at 19° C.) before it was pelletized. The output ratefor this process was 30 pounds/hr (13.6 kg/hr). A total of 300 pounds(136.2 kg)of the coupled resin was collected for further study. Thefinal resin (after treatment) had a measured 1.0 g/10 min melt index and0.919 g/cc density.

[0124] Film Fabrication

[0125] Films were fabricated in a blown film extruder having a 2.5 inch(6.25 cm) single screw commercially available from BattenfeldGlouscester Engineering Inc under the trade designation Model 22-01using the detailed fabrication parameters as follows: Die gap: 70 mil(1.75 mm) Die type: Sano Die diameter: 6 inches (15.2 cm) Screw type:Barr ET Output rate: 188 lb/h (85.1 kg/hr) (10 lb/hr/in die) (4.53kg/hr/m die) Melt Temp: ˜400° F. (204° C.) Temperature profile: 350° F.,425° F., 290° F., 290° F. (177° C., 218° C., 143° C.. 143° C.) CoolingAir: yes Blow up ratio: 2.0 & 2.9 Film gauge: 6.0 mil (0.15 mm) Shear atthe die: ˜106 /s (metric unit)

[0126] 3000 ppm of SiO₂was added as an antiblock to all of the resins,and 1000 ppm of polymer processing aid commercially available from 3MCo. under the trade designation Dynamar-5920 was added to all theresins. The SiO₂ and Dynamar-5920 processing aid were dry-blended withthe pellets; the additive blended pellets were then fed to the extruderto prepare the film.

[0127] Puncture at room temperature was measured using an instrument forthe purposed commercially available from Instron Inc. under the tradedesignation Instron Model 4201 with a hardware upgrade commerciallyavailable from Sintech Inc and a testing frame commercially availablefrom Sintech Inc. under the trade designation MTS Sintech ReNew testingframe along with software commercially available from Sintech Inc. underthe trade designation Sintech (Version 3.08) Testing Software. Foursamples of each film with dimensions of 6″×6″ (15×15 cm) were measuredusing a round-specimen holder 12.56″ (31.9 cm) square. A puncture probeis a 1/2″ (1.27 cm) polished stainless steel ball with 7.5″ (18.75 cm)maximum travel and travel speed of 10 inches/min (25.4 cm/min) Theenergy required to break the film was measured.

[0128] Elmendorf Tear Strength is measured at 23 ° C. according to theprocedures of ASTM D1922. MD (Machine Direction) Ult (ultimate) TensileStrength and CD (Cross Direction) Ult Tensile Strength are measuredaccording to the procedures of ASTM D638. Results of these measurementsare shown in Table 1: TABLE 1 Mechanical Properties of Film Propertiesof Film Ex 1 Ex. 2 100% DOWLEX ™ Std 100% Std 2035 Dev DOWLEX ™ Devpolyethylene 2035 1250 ppm BSA polyethylene (2.0)* 1250 ppm BSA (2.9)*Extruder Pressure 1720 1720 (psi) Elmendorf Tear Strength (23° C.) (ASTMD1922) MD Tear Strength 1104.00 147.00 1384.30 85.80 (g) CD TearStrength 2060.80 94.90 1900.80 86.50 (g) Puncture at Room Temp. Energyto Break (in- 35 2 44 4 lb) MD Ult Tensile 3530 524 3410 670 Strength(psi) ASTM D638 MD Elongation at 740 73 740 97 Break (%) ND TensileYield 1480 26 1480 32 (psi) CD Ult Tensile 3480 345 3540 496 Strength(psi) ASTM D638 CD Elongation at 760 52 750 68 Break (%) CD TensileYield 1610 9 1540 18 (psi) Haze (%) (ASTM 27.2 0.1 22.0 0.3 D1003)

[0129] TABLE 2 Metric conversions of measurements Properties of Film Ex1 Ex. 2 100% DOWLEX ™ 2035 metric 100% DOWLEX ™ 2035 metric polyethylene1250 ppm conversion polyethylene 1250 conversion BSA (2.0)* ppm BSA(2.9)* Extruder Pressure (psi) 1720 11.86 1720 11,86 Mpa Elmendorf TearStrength (23° C.) (ASTM D1922) MD Tear Strength (g) 1104.00 same 1384.30CD Tear Strength (g) 2060.80 1900.80 Puncture at Room Temp. Energy toBreak (in-lb) 35 40.25 44 50.6 (cm/kg) MD Ult Tensile Strength 353024.33 3410 23.51 (psi) ASTM D638 MD Elongation at Break 740 740 (%) MDTensile Yield (psi) 1480 10.20 1480 10.20 Mpa CD Ult Tensile Strength3480 23.99 3540 24.4 (psi) ASTM D638 CD Elongation at Break 760 750 (%)CD Tensile Yield 1610 11.10 1540 10,6 (psi) Mpa Haze (%) (ASTM D1003)27.2 22.0

Comparative Samples A and B

[0130] Samples of 2.0 kg each of an ethylene-octene copolymer withMw/Mn=3.26, Mw=71, 100, having a melt index of 6.0 g/10 min., and adensity of 0.919 g/cc commercially available from The Dow ChemicalCompany under the trade designation DOWLEX™ 2035 polyethylene resin(containing the same additives as in Example 1) for Comparative Sample Aand a linear low density ethylene/octene copolymer with Mw/Mn=3.96,Mw=114,800 melt index=1.0 g/10 minutes and density of 0.92 g/cm³commercially available from The Dow Chemical Company under the tradedesignation DOWLEX™ 2045A polyethylene resin having an additive packageconsisting of 1250 ppm of Calcium Stearate, 200 ppm of antoxidantcommercially available from Ciba Geigy Corp. under the trade designationIrganox 1010, and 1600 ppm of phosphite antioxidant commerciallyavailable from Ciba Geigy Corp. under the trade designation Irgaphos168, for Comparative Sample B were prepared according to the followingprocedure:

[0131] Each resin is imbibed with BSA of the concentration designated inTable 3 by the procedure:

[0132] 1) The designated amount of the resin was weighed into a highdensity polyethylene bag.

[0133] 2) An amount of a 5 weight percent solution of BSA intetrahydrofuran (THF) corresponding to the designated amount of theazide was prepared.

[0134] 3) The solution of BSA was dispensed over the resin in multipleportions from a syringe having an industrial blunt-tipped needle.

[0135] 4) The bag was closed and the resin was vigorously mixedfollowing the addition to ensure homogeneity.

[0136] 5) The bag was opened in a fume hood and the THP was allowed toevaporate for a minimum of 2 hours to prepare dry pellets.

[0137] 6) The coated dry pellets were mixed one final time and then putin the hopper of a feeder for metering to an extruder.

[0138] A total of 10.0 g of the BSA was deposited on each 2.0 kg sample,providing a 500 ppm (weight/weight) level of the BSA on each sample.

[0139] After Step 6 of the procedure, the coated pellets were fed into atwin screw extruder having a screw diameter of 18 mm commerciallyavailable from Haake, Inc. under the trade designation Haake PolylabMicro 18 twin screw extruder. The extruder has Zones 1-5 from the feedzone to the discharge die of the extruder; these zones are 3.5 inch longheated blocks, centered 4 inches, 7.5 inches, 11 inches, 14.5 inches,and 18 inches from the center of the feed throat for the extruder forZones 1, 2, 3, 4, and 5 respectively. Temperatures set for each zone are50° C., 75° C., 85° C., 90° C., and 93 ° C., respectively with measuredtemperatures of 53.8° C., 75° C., 84.9° C., 90° C., and 93.1° C.measured for Zones 1, 2, 3, 4, and 5, respectively. The temperature wasmeasured using thermocouples that contact in the body of the extruderbarrel. The die temperature was set to and measured at 93° C., with amelt temperature of 100° C. Die pressure was 1700 psi (11,721 kPa); feedrate was 1.0 lb/hr (0.45 kg/h); extruder screw speed was 50 rpm(revolutions per minute) with an extruder torques of 5700 meter grams.The extruded polymer is drawn through a water bath for cooling and theresulting polymer strands are cut into pellets.

[0140] The resulting polymers had significant black specks as noted byvisual inspection of the pellets. The specks were actually incorporatedinto the each of the pellets. No film could be produced due to theamount of black specks.

EXAMPLE 3

[0141] Example 3 was prepared as though for a concentrate, or masterbatch. A 0.038 lb (0.017 kg) sample of BSA, 0.100 lb (0.045 kg) ofmineral oil (commercially available from Witco Corp. under the tradedesignation Kaydol), and 24.863 lb (11.28 kg) of an ethylene-octenecopolymer with Mw/Mn =3.39, Mw=94,300, having a melt index of 2.3 g/10min., and a density of 0.917 glcc commercially available from The DowChemical Company under the trade designation Dowlex™ 2047 polyethyleneresin (containing 500 ppm polyphenolic antioxidant commerciallyavailable from Ciba Geigy Corporation under the trade designationIrganox 1076 and 1600 ppm phosphite stabilizer commercially availablefrom Ciba Geigy Corporation under the trade designation Irgaphos 168)was tumble blended for 60 minutes in a poly bag lined fiber drum Aconcentrate was formed in the mineral oil. The concentrate coatedpellets were then extruded under the conditions described in ComparativeSample A, to provide an ethylene-octene copolymer with modifiedrheological properties

EXAMPLES 4 and 5

[0142] Preparation of Concentrate 1

[0143] A 10 weight percent concentration of BSA in an ethylene-octenecopolymer with Mw/Mn=2.03, Mw=110,800, having a melt index of 5.00 g/10min., and a density of 0.870 g/cc commercially available from The DowChemical Company under the trade designation AFFINITY™ EG8200 polyolefinplastomer (referred to hereinafter by the trade designation) for amaster batch (Concentrate 1) was formed by mixing a sample of 27.2 g ofBSA with 243 g of the AFFINITY™ EG 8200 polyolefin plastomer (containing500 ppm of hindered phenolic stabilizer commercially available from CibaGeigy Corporation under the trade designation Irganox 1076 and 800 ppmstabilizer believed to betetrakis-(2,4-ditertiarybutyl-phenyl)-4,4′-biphenyl phosphonitecommercially available from Sandoz Chemical Company under the tradedesignation P-EPQ stabilizer) and 2 g of mineral oil (commerciallyavailable from Penreco Corp. under the trade designation Drakeol 35).Pellets were put into a five gallon polyethylene bag, the BSA powder wasadded in the center, then the oil squirted from a syringe in a circlearound the powder pile. The bag was then closed at the top, leaving anair space above the mixture and shaken until it appeared to becompletely mixed, i.e., no loose powder was visible in the bag, forapproximately two minutes. The resulting mixture was extruded on a twinscrew extruder having a screw diameter of 18 mm commercially availablefrom Haake, Inc. under the trade designation Haake Polylab Micro-18 twinscrew co-rotating extruder at 50 rpm with the following temperatureprofile for each zone: Zone 1, 2, 3, 4, and 5 set at 70, 80, 90, 90, 90°C., respectively. The strand from the extruder was passed through achilled water bath then chopped by a strand cutter commerciallyavailable from Berlyn under the trade designation Pell-2 strand cutter.The extruder screw was comprised of 9 elements with the followingconfiguration (referring to the length of the screw stack element in mm,and the angle of pitch of the screw on the mixing element in degrees):90 mm & 40°, 90 mm & 40°, 90 mm & 40°, 60 mm & 40°, 60 mm & 40°, 30 mm &40°, 30 mm & 40°, 90 mm & 30°, screw tip.

[0144] Preparation of Concentrate 2

[0145] The procedure for preparation of Concentrate 1 was repeated toform Concentrate 2 except that 13.6 g of BSA were used to form a 5weight percent concentration of BSA in the ethylene- octene copolymercommercially available from The Dow Chemical Company under the tradedesignation AFFINITY™ EG 8200 polyolefin plastomer referred tohereinafter by the trade designation and containing 500 ppm Irganox 1076stabilizer and 800 ppm P-EPQ stabilizer for a master batch (designatedConcentrate 2).

EXAMPLE 4

[0146] A 19.693 lb (8.93 kg) sample of an ethylene-octene copolymer withMw/Mn=3.39, Mw=94,300, having a melt index of 2.3 g/10 min., and adensity of 0.917 g/cc commercially available from The Dow ChemicalCompany under the trade designation DOWLEX™ 2047 polyethylene resinmixed with 0.307 lbs (0.139 kg) of Concentrate 1 was placed in a fiberdrum which had an HDPE (high density polyethylene) bag liner and tumbleblended for approximately 60 minutes (rotation about 10 RPM). Theresulting mixture was fed into the twin screw extruder used inExample 1. The extruder actual temperatures are 130, 175, 215, 221, and221° C. for Zones 1-5, respectively, from the feed to the discharge(die) of the extruder. The melt temperature and die temperatures were230 and 220° C., respectively. The resulting melt-extruded resin ranthrough a water cooling bath (at 19° C.) before it is pelletized. Theoutput rate for this process is 30 pounds/hr (13.6 kg/h), and 300 pounds(136.2 kg) of the coupled resin is collected for further study.

[0147] The final resin (after treatment) has a measured 1.0 g/10 minmelt index and 0.919 g/cc density.

EXAMPLE 5

[0148] For Example 5, the procedure of Example 4 is repeated except thatConcentrate 2 is used in an amount of 0.65 lb (0.29 kg) with 24.35 lb(11.04 kg) of the resin.

[0149] Film Extrusion

[0150] Films were fabricated in a blown film extruder having a 1.25 inch(3.175 cm) single screw commercially available from Killion Extruders,Inc. under the trade designation Killion model KL125 using the detailedfabrication parameters as follows: Die gap: 60 mil (1.52 mm) Die type:Sano Die diameter: 3 inches (0.076 m) Screw type: single Output rate:˜10 lb/h (4.5 kg/h) Melt Temp: ˜450° F. Temperature profile: 350, 400,450, 450° F. (177, 204, 232, 232° C.) respectively) Cooling Air: no Blowup ratio: 1.8 Film gauge: 3.0 mil (0.076 mm) Shear at the die: 18 1/sec

[0151] Viscosities are determined as described previously, I10 and I2are determined by the procedure of ASTM D 1238 and the results of theseanalyses are recorded in Table 3. TABLE 3 Rheology of Coupled LLDPE(linear low density polyethylene) Using Concentrates of BSA PropertiesEx. 3 Ex. 4 Ex. 5 Concentrate Mineral Oil (master (Master vehicle batch)Batch) AFFINITY ™EG82 AFFINITY ™ 00 polyolefin EG8200 plastomerspolyolefin plastomers concentration of 27.5 weight 10 weight 5 weightBSA in vehicle percent percent percent (concentrate) concentration of1500 ppm BSA 1360 ppm BSA 1300 ppm BSA BSA in polymer Base ResinDowlex ™ Dowlex ™ Dowlex ™ 2047 2047 2047 polyethylene polyethylenepolyethylene I2 0.18 0.42 0.45 I10/I2 21.9 14.5 15.6 0.1 Vis (Pa - s)5.0 E4 3.0 E4 5.0 E4 0.1/10 Vis. 33 20 33 Back Press. 17236 +/− 14479+/− 15168 +/− 2068 2068 2068

[0152] The results in Table 6 indicate that the BSA is very effectivewhen added using a concentrate (Ex 3, 4 and 5). The improvement inrheology is measured by the increase in I10/I2 or 0.1/100 viscosity.

EXAMPLES 6 AND 7 AND COMPARATIVE SAMPLE C

[0153] The resin used for Examples 6 and 7, and Comparative Sample C isan ethylene-propylene-ethylidene norbornene terpolymer with Mw/Mn=3.73,Mw=136,200, having a melt index (I2) of 1.0 g/10 min., and a density of0.88 g/cc commercially available from DuPont Dow Elastomers under thetrade designation Nordel IP NDR 3720P hydrocarbon rubber (containing1000 ppm Irganox 1076 stabilizer).

[0154] For Example 6, a concentrate is made on a twin screw extruderwith am 18 mm barrel, commercially available from Haake, Inc. under thetrade designation Haake Polylab Micro 18 by dry blending 34.05 g of theBSA and 5.0 lb (2.27 kg) of an ethylene-octene copolymer withMw/Mn=1.90, Mw=19,000, having a melt index of 1000 g/10 min., and adensity of 0.87 g/cc commercially available from The Dow ChemicalCompany under the trade designation XUS-59800.02 polyolefin elastomer.

[0155] This dry blend is extruded at a low temperature of 110° C. toavoid reacting the carrier wax with the BSA The resulting melt blendedconcentrate is water quenched by drawing through a water bath at 18° C.and chopped into pellets. A total of 10 kg of anethylene-propylene-ethylidene norbornene terpolymer with Mw/Mn=3.73,Mw=136,200, having a melt index of 1.0 g/10 min., and a density of 0.88g/cc commercially available from DuPont Dow Elastomers under the tradedesignation Nordel IP NDR 3720P hydrocarbon rubber, pellets and 240 g ofthe concentrate are dry blended and then extruded as described below.

[0156] For Example 7, an oil coated blend is made by adding 25 g of amineral oil commercially available from Witco Corp. under the tradedesignation Kaydol to 10 kg of pellets of Nordel IP NDR 3720Phydrocarbon rubber and then tumble blended for a period of 1 hour atambient temperature to coat the pellets with the oil. Then 12.5 g of BSAis added to the oil coated pellets and again tumbled blended by hand fora period of 5 minutes at a temperature of 25° C. to mix the BSA into thecoating of oil to form a concentrate of BSA in the oil. The resultingblend is also extruded as described below.

[0157] For Comparative Sample C, an untreated sample of 5 lb. (2.27 kg)of the Mordel IP NDR 3720P hydrocarbon rubber is extruded without BSA toexpose it to the same conditions as Example 2 and is referred to hereinas Comparative Sample C.

[0158] The Examples 6 and 7 and Comparative Sample C are melt blended atthe conditions below on the twin screw extruder used in Example 1.

[0159] The following extrusion conditions are used:

[0160] Zone 1 Temp Set 80° C.

[0161] Zone 2 Temp Set 130° C.

[0162] Zone 3 Temp set 190° C.

[0163] Zone 4 Temp set 190° C

[0164] Zone 5 Temp set 190° C.

[0165] Die Temp set 190° C.

[0166] Extruder RPM's set to 250

[0167] Water Bath 57° F. (13.9° C.)

[0168] Output Rate 17-23 lb/hr (7.7-10.4 kg/h)

[0169] Properties of the resulting polymers are measured as describedfor Example 1.: Mooney viscosity is determined according to theprocedure of ASTM 1646-92 (at 25°C., 9 minutes run time, using a 38.1 mmdiameter rotor at a rotor speed of 0.02 rad/sec). TABLE 4 Properties ofRheology Modified EPDM (ethylene propylene diene monomer rubber) withBSA Example or Comparative Mooney Gels Sample Azide viscosity (percent)C.S. C 0 18.2 0.967 Ex. 6 1250 ppm 24.3 0.827 1000 m.i. Conc. Ex. 7 1250ppm Oil 25.3 0.935 coated

[0170] TABLE 5 Rheology of EPDM (ethylene propylene diene monomerrubber) Modified with BSA Visc % Visc. % Visc. Visc Visc 0.1/ Tan ChangeChange % Tan 0.1 100 100 0.1 @ 0.1 @ 100 Change Base 241810 13516 17.892.0618 Polymer Nordel IP NDR 3720P hydro- carbon rubber Ex. 6 82242015331 53.64 0.781 240 13 −62

[0171] Preparation of Rheology Modified HDPE in a Twin Screw Extruder

[0172] As Example 8, a sample of an ethylene-butene copolymer with amelt index (I5) of 0.43 g/10 min., an I 21.6/I5 of 24.2 g/10 min., andan I10/I2 of 19.2 (as measured on an instrument commercially availablefrom Custom Scientific Instruments, Inc. under the trade designationMicroMelt Indexer Model #CS127, run at 190° C. with 2.16 Kg weight forI2 according to ASTM 1238 but with 1/6 sample size), and a density of0.955 g/cc commercially available from The Dow Chemical Company underthe trade designation HDPE 40055E polyethylene (hereinafter the HDPE)having properties of melt strength and melt index listed hereinafter andcontaining 335 ppm of a hindered polyphenolic stabilizer commerciallyavailable from Ciba Geigy Corporation under the trade designationIrganox 1010 stabilizer and 1005 ppm of phosphite stabilizercommercially available from Ciba Geigy Corporation under the tradedesignation Irgaphos 168 stabilizer; and as Example 9 a sample of anethylene-butene copolymer with a melt index (I5) of 0.23 g/10 min., anI10/I2 of 22.4 according to the test method used for Example 8, and adensity of 0.935 g/cc commercially available from BASF Corp. under thetrade designation Lupolen 4261A (properties of melt strength and meltindex listed hereinafter), are rheology modified with BSA at levels of400 ppm and 200 ppm BSA respectively. The BSA is added to the HDPE as aconcentrate of 1 weight percent BSA in poly (ethylene-co-acrylic acid)commercially available from The Dow Chemical Company under the tradedesignation PRIMACOR 3150 adhesive copolymer, (hereinafter EAA) having 3percent acrylic acid. The 1 percent concentrate is prepared from a“superconcentrate” of 10 weight percent BSA in the same EAA. Thesuperconcentrate is prepared by adding 20 g BSA to 180 g EAA and mixingin a mixer commercially available from Haake, Inc. under the tradedesignation Rheocorder at 120° C. at 20-40 RPM for 10 minutes.

[0173] A 1 weight percent BSA concentrate is then prepared by mixing thesuperconcentrate with additional EAA on an extruder commerciallyavailable from Haake, Inc. under the trade designation Haake PolylabMicro-18 18 mm Leistritz twin screw extruder. The extruder screws werecomprised of 7 elements with the following configuration (referring tothe length of the screw stack element in mm, and the angle of pitch ofthe screw on the mixing element in degrees): 90 mm 40°, 90 mm 40°, 90 mm40°, 60 mm 40°, 60 mm 40°, 90 mm 30°, 60 mm 30°. The tips are allforwarding elements.

[0174] Extrusion profile for concentrate preparation:

[0175] Zone 1 75° C.

[0176] Zone 2 100° C.

[0177] Zone 3 115° C.

[0178] Zone 4 120° C.

[0179] Zone 5 120° C.

[0180] Die 120° C.

[0181] Melt 127° C.

[0182] Torque 2500 mg (meter-grams)

[0183] RPM 80

[0184] Press ˜1000 PSI (6895 kPa)

[0185] Rate 34-36 g/min

[0186] Example 8, Using a High Density Polyethylene

[0187] For Example 8 the HDPE described previously is prepared by tumbleblending 73 lb (33 kg) of 2.74 lb (1.24 kg) of 1 weight percent BSAconcentrate with 70.26 lb (31.9 kg) of the HDPE. The tumble blendedmaterial is fed to the twin screw extruder described in Example 1 underthe conditions outlined in Example 9, extruded, cooled in a water bathand strand chopped into pellets.

[0188] Example 9 Using an Ethylene-butene Copolymer

[0189] Example 9 is prepared by tumble blending 75 lb (34 kg) of 1.5 lb(0.7 kg) of 1 weight percent BSA concentrate with 73.5 lb (33.3 kg) ofLupolen 4261A polymer. The tumble blended material is fed to the twinscrew extruder used in Example 8 under the conditions outlined below,extruded, cooled in a water bath and strand chopped into pellets.

[0190] Extruder conditions for Examples 8 and 9:

[0191] Zone 1 75° C.

[0192] Zone 2 134° C.

[0193] Zone 3 191° C.

[0194] Zone 4 226° C.

[0195] Zone 5 225° C.

[0196] Die 230° C.

[0197] Melt 241° C.

[0198] Torque 76 percent

[0199] RPM 200

[0200] Press 925 PSI (6377 kPa) (Example 9) 750-760 PSI (5171-5240 kPa)(Example 8)

[0201] Rate 31-32 lb/hr (14-14.5 kg/hr) (Example 9) 33.7-36.3 lb/hr(15.3-16.5 kg/hr) (Example 8) Melt Strength of Modified Materials:Velocity Melt Strength Sample (mm/sec) (cN) Lupolen polymer 120 32Lupolen polymer + 200 ppm 24 80 40055E polyethylene 55 19 40055Epolyethylene + 400 ppm 36 36

[0202] The data obtained by analysis of the products of Examples 8 and 9shows an increase in melt strength after low levels of treatment withcoupling agent.

What is claimed is:
 1. A process of reacting a poly(sulfonyl azide) witha polymer comprising steps (a) forming a first admixture, hereinafterreferred to as a concentrate, of a first amount of a first polymer or ina liquid which does not require removal from the polymer, hereinafterdiluent, and a poly(sulfonyl azide); (b) then forming a second admixtureof the first admixture with a second amount of at least one secondpolymer, hereinafter second polymer composition; and (c) heating thesecond admixture at least to the decomposition temperature of thecoupling agent for a time sufficient to result in coupling of polymerchains.
 2. The process of claim 1 wherein the diluent is a non-volatile,non-polar compound such as mineral oil in which the poly(sulfonyl azide)is sufficiently miscible to disperse the poly(sulfonyl azide) in thesecond polymer.
 3. The process of claim 1 wherein step (b) includesintroducing a poly(sulfonyl azide) in liquid form, in a slurry or otheradmixture of poly(sulfonyl azide) in a liquid diluent, into a devicecontaining the second polymer.
 4. The process of claim 3 wherein thesecond polymer into which the poly(sulfonyl azide) is introduced issoftened, molten or melted polymer.
 5. The process of claim 3 whereinthe polymer into which the poly(sulfonyl azide) is introduced is inparticulate form.
 6. The process of claim 1 wherein step (b) takes placein melt processing equipment.
 7. The process of claim 1 wherein theprocess includes forming a first admixture of a first amount of a firstpolymer and a poly(sulfonyl azide) at a temperature less than thedecomposition temperature of the poly(sulfonyl azide), and then forminga second admixture of the first admixture with a second amount of thefirst polymer.
 8. The process of claim 7 wherein the first polymer andpoly(sulfonyl azide) are admixed by melt blending.
 9. The process ofclaim 1 wherein a first polymer is used in step a(a) and some couplingoccurs during step (a), but some of the poly(sulfonyl azide) remainsunreacted until the resulting concentrate is blended into the secondpolymer composition.
 10. The process of claim 1 wherein the diluent is aliquid at room temperature or low melting solid at room temperature,that is has a melting point below about 50° C.
 11. The process of claim1 wherein the first polymer is low melting, that is has a melting pointbelow about 110° C. or a melt index, I2, of at least about 0.5 g/10 min.12. The process of claim 11 wherein the first polymer is selected fromethylene alpha olefin copolymers, where the alpha olefins are of 3 to 20carbon atoms, have a density range of at least about 0.855 g/cc to about0.955 g/cc or have a melt index, I2, of at least about 0.5 g/10 min;ethylene acrylic acid; ethylene vinyl acetate, ethylene/styreneinterpolymers or combinations thereof.
 13. The process of claim 12wherein the first polymer has a melting temperature of less than about150° C.
 14. The process of claim 1 wherein the concentrate is dryblended with pelleted polymer
 15. The process of claim 1 wherein theconcentrate is injected as molten concentrate into molten second polymercomposition.
 16. The process of claim 1 wherein the concentrate isformed on the surface of a polymer to be coupled.
 17. The process ofclaim 16 wherein the diluent is coated on a comminuted second polymercomposition by stirring or tumbling comminuted polymer with a diluent.18. The process of claim 1 wherein steps (a) and (b) take place in thesame vessel.
 19. The process of claim 1 wherein steps (a) and (b) takeplace in the post-reactor area of a polymer processing plant.
 20. Theprocess of claim 1 wherein the first and second polymers are of the samecomposition.
 21. The process of claim 1 wherein the first and secondpolymers are of the different compositions.
 22. The process of claim 1wherein the poly(sulfonyl azide) is present in an amount less than about0.5 weight percent based on the total weight total polymers.
 23. Theprocess of claim 22 wherein the poly(sulfonyl azide) is present in anamount greater than about 0.01 weight percent based on the total weightof polymers.
 24. A composition which is obtainable from a process ofreacting a poly(sulfonyl azide) with a polymer comprising steps (a)forming a first admixture, hereinafter referred to as a concentrate, ofa first amount of a first polymer or in a liquid which does not requireremoval from the polymer, hereinafter diluent, and a poly(sulfonylazide) (b) then forming a second admixture of the first admixture with asecond amount of-at least one second polymer, hereinafter second polymercomposition, and (c) heating the second admixture at least to thedecomposition temperature of the coupling agent for a time sufficient toresult in coupling of polymer chains.
 25. The composition of claim 24having no more than about 5 weight percent gels as measured by xyleneinsolubility of the gels.
 26. A process of preparing shaped polymerarticles by forming a composition of claim 24 in a melted state into anarticle.
 27. The process of claim 26 which comprises thermoforming,injection molding, extrusion, casting, blow molding, foaming or blowing.28. An article comprising a composition of claim
 24. 29. A compositionwhich is a blend of any composition of claims 24 with at least onepolymer of a composition different from that of the first or secondpolymer.